Monitoring

Early warning of water flooding

The whole idea of why to invest 1000 - 5000 Euro for water detection system against simple water spot detector is based on the assumption that if you react within first minutes, repair costs will be 10x lower compared to 10 cm of water in whole building. 

Every building has a certain capacity of water that can be easily cleaned. You just have to be quick.

In order to respond quickly, you must have:

1. Water sensing cables installed in the right places;
2. Properly configured devices analyzing WLD zones + Portal (optional);
3. Alert escalation + processes;
4. Test the whole system from time to time.

Choosing the Right Water Leak Detection Device

HW group's Water Leak Detection system consists of a WLD sensing cable and a connected alarming device. There are currently 4 different remote monitoring devices with WLD zone input(s). Let's take a look at the differences between them.

	WLD2	SD-WLD	NB-WLD	WLD-Relay
WLD zones	4	1	1	1
NB-IoT (Cellular network)	-	-	yes	-
LAN (RJ45)	yes	yes	-	-
Wi-Fi	yes	yes	-	-
1Wire-UNI (RJ11)	-	-	-	yes
Relay output (NO/NC)	-	-	-	yes

WLD2: Standalone Water Leak Detection

With 4 detection zone inputs (4x 185m of water sensing cable) and PoE / 5V power adapter, the WLD2 is the most universal water detection device. The WLD2 can send email alerts by itself or through an external Portal (SensDesk technology).

4 WLD zones means the WLD2 can detect / identify water in 4 independent areas. 

• Water detection in each zone can be indicated by: 
  • External Relay output (with or without Portal);
  • Email (with or without Portal);
  • SMS / Call (with SMS GW or with Portal).

When customers use the Portal (even free HWg-cloud.com), there can be activated "Device Invalid Alert" feature. The portal will alert you if there is no power / communication with the portal. 

Product web page: https://www.hw-group.com/device/wld2

SD-WLD

The SD-WLD is a simple Water Leak Detection device with only 1 WLD zone input. Powered by PoE / 5V power supply. The SD-WLD is easy to install, there is no local configuration required, but external Portal is mandatory. Device itself can't send alarm emails without Portal.

• SD-WLD can be powered by PoE;
• Portal connectivity is required;
• Portal provides centralized alert management (Email, SMS, Calls, SNMP, Relay Output);
• Portal provides "Device Invalid Alert" feature. The portal will alert you if there is no power/communication with the portal. 

Product web page: https://www.hw-group.com/device/sd-wld

NB-WLD

NB-IoT cellular connected device for remote monitoring of 1 WLD zone (60 / 185 meters of sensing cable). 3-year SIM contract included, battery operation for up to 2 years.
Powered by an internal battery / 5V power supply, the NB-WLD is an ingenious device to warn you, even if there is a power failure at the remote location. External portal is mandatory, device itself can't send alerting emails without the Portal.

• NB-WLD can be powered from internal battery for up to 2 years;
• When powered by internal battery, the maximum WLD zone length is 60m;
• Portal connectivity is required;
• Portal centralized alert management (Email, SMS, Calls, SNMP, Relay Output);
• Portal provides "Device Invalid Alert" feature. The portal will alert you if there is no power/communication with the Portal.

Product web page: https://www.hw-group.com/device/nb-wld

WLD Relay

The WLD Relay is a 1-WLD zone sensing device with 2 output options. Flooding can be indicated by a switching relay output or as a 1-Wire UNI (RJ11) sensor. Via RJ11 it can be connected to many HWg devices with external sensor ports.

• WLD Relay is a universal device (WLD detector) that can be connected to any security system or DI (Dry Contact) on the IP camera, etc;
• Water detection is indicated locally by red LED diode on the device. 

Product web page: https://www.hw-group.com/sensor/sensor-wld-relay-1w-uni

Alerting reality: Every minute counts

We are talking about long-term monitoring sensor installation. That means the customer installs a sensor, tests it, and it sits there quietly for 3-7 years. After that, you need to be alerted and "woken up" within 1-5 minutes. Every minute counts. Here are some best practices: 

• Test the system once a year, that's best practice; 
• Do not use public SMTP server for email alerting (use Portal or private SMTP server);
• Email is not enough;
• Use SMS / Calls for water alerting;
• Use proper names in the WLD zone names; 
• Try to figure out after 7 years what "server room C flooded" is when you're responsible for 3 locations;
• Centralized management (Portal) of alerts is much better; 
• Very few customers change the phone numbers/emails of the recipients in the devices.

 

	WLD2	SD-WLD	NB-WLD	WLD-Relay
SensDesk Portal Connectivity	Yes	Yes (mandatory)	Yes (mandatory)	Via external device
Web interface, SMTP	Yes	Via portal	Via portal	-
E-mail alert	Yes	Via portal	Via portal	-
SMS & Call alert	Via SMS Gateway or Portal	Via portal	Via portal	-
Disconnected device alert	Via portal	Via portal	Via portal	Yes (sensor = -999)
Remote relay alert	Yes	Via portal	Via portal	Via external device
Multigraphs, PDF reports	Via portal	Via portal	Via portal	-
Open API (SNMP, XML)	Yes	Via portal	Via portal	-

Summary of WLD System by HW group

WLD System from HW group will help any customer to safely monitor the remote site for very small amounts of water, and provide timely alerts via various mediums when the liquid is detected.

You can find more details in our summary “Water Leak Detection (WLD) system” article: https://www.hw-group.com/support/water-leak-detection-wld-system

Take a look at the video explaining all the different options of the WLD system.

WLD (Water Leak Detection) from HW group uses a sensing WLD cable to detect water along the entire length of the sensing cable. It’s a reliable system with early warnings from the very first drops of the water in the critical points.

HW group produces several devices with WLD zone input on the LAN devices (SD-WLD, WLD2, Perseus 150) or NB-IoT (NB-WLD). However, many customers want to use only WLD detection and connect it to their own system. For them we produce the WLD Relay, which can be powered by 12V and switches a simple relay output when water is detected.

WLD sensing cable features

It's hard to explain why the HW Group's WLD sensor cable is so popular. Our customers love it simply because this water leak detection cable does not generate false alarms.

• No Bend Limit

Most of the other water detection sensing cables are limited to a minimal diameter. If it bends too much, it will generate a false water alarm. It's a fundamental problem for many installations. 
The WLD sensing cable doesn't have a bend radius limit. It can be knotted and still work, which means installation is easy and doesn't require any special training. 

• No Grip Limit

Point pressure within a reasonable range won't change the functionality of the cable. You can step or press on the WLD sensing cable without triggering an alarm. It could even be routed over the door sill.

• No Twist Limit

Like any other electrical cable, the WLD sensing cable can be twisted. No twist limit for the WLD sensing cable also means that no cable movement after installation will cause a false alarm.

• No Reuse Limit

Once the liquid has been detected and hopefully stopped from flooding the monitored facility, the cable simply dries out and resumes its primary function.

Water detection on 185m sensing cable with relay output

The WLD Relay has 1 WLD zone input with a green terminal block. A WLD connection cable (2m) and one or more segments of WLD sensing cable are connected. The total length of the WLD zone can be up to 185 including the length of the non-sensing cable. 

Relay output responds to the smallest amount of water, ethylene glycol or other conductive liquid water along the entire length of the sensing cable. The relay will also alarm if the WLD sensing cable is disconnected. 

The WLD relay requires a 12V power supply.

WLD-Relay as RJ11 sensor

The same device WLD-Relay can also be used as RJ11 (1W UNI) sensor. A WLD zone can be connected to any HWg device with an RJ11 port (STE2 family, Poseidon2 family, Ares 12, ...). 

The WLD Relay as 1W-UNI sensor supports three states: 

• OK
• Water 
• Disconnected

This means that the operator of the remote monitoring solution would know if something has happened to the cable itself or if there is water flooding. There would be no surprise leakage if the cable were accidentally broken or disconnected.

 

WLD relays can be ordered as:

• Sensor WLD Relay 1W-UNI 

Plain unit - white box only. 

• WLD Relay 

Set with power supply, 2m + 2m WLD sensing cable

WLD-Relay in action - 1200 meters of WLD sensing cable

WLD relay can be massively scaled, as we have shown in the ONSEMI case study, where the water monitoring system counts 28 relay-based zones with a total of more than 1200 meters of sensor cable. All of this is connected to a single Damocles2 monitoring unit responsible for alarming and alerting.

Take a look at the video we made about the WLD Relay.

Traditional water spot (flood) detectors are inexpensive, easy to install, and popular in many industries. They typically use 2 or 4 pins, and water is detected when those pins are connected. The problem is that there must be a continuous layer of water to detect the presence of water. 

The spot water detectors should be installed with care and precision, at lower surface levels. In the real world, there is a high probability of a very late alarm. You will be alerted when everything is already flooded, just because a detector was placed where the water is coming from at the end of a flood disaster. We call this type of late warning a "swimming invitation", not an early warning. 

Businesses and industries where the detection and control of water and other liquids is critical know from experience the importance of early warning with the first few drops of water. The first few minutes are critical to preventing ultimate damage. 
Final damage is not the cleaning service and drying out of the building, but the company being out of business, damaged (unreliable) servers, etc.

	Spot water (flood) detection	Sensing cable water leak detection
System cost	Up to €100	From €400
Installation time	5 min	1 hour / zone
What is detected	Water layer (2mm min) on 2 contacts	First drops of water along the entire length of the sensing cable
Late alert (swimming invitation)	Highly likely	Unlikely
False alarm probability	Unlikely	Unlikely
Early warning	Unlikely	Highly likely

Water spot (flood) detection

Flood detectors only detect water in one location and must be completely flooded. This means that you will not be alerted immediately when a water pipe breaks, but only when the area is significantly flooded. Therefore, it is not the ideal solution for data centers etc. where you need to be alerted before the water reaches your IT infrastructure. 
Only the use of the water detection cable ensures this.

Using the Water spot detection:

• Easy to use detector
• High risk of improper installation
• Swimming invitation alerts only

 

Sensing cable water leak detection

Using Water Leak Detection with a sensing cable you can detect the first drops anywhere in the monitored room/area. This early warning can prevent significant damage to IT or other infrastructure. Water Leak Detection with sensing cable is recommended in IT, data centers, engineering and medical environments, or anywhere where water damage would be very costly.
A sensing cable can be installed under raised floors in data centers, wrapped around pipes, run along walls, etc. Custom solutions are available for any requirement.

Using the WLD sensing cable:

• Placement of the sensing cable must be considered
• WLD system is reliable (no false alarms)
• WLD system is capable of alarm
• Detects the first drops of water along the entire length of the sensing cable
• Sensing zone can be easily covered by combination of sensing & non-sensing cable

WLD system
The real early warning is exactly why having a water leak detection system in place, although much more expensive, is preferred by many. HW group's remote monitoring ecosystem includes several devices based on the unique sensing cable that detects even a few drops of water.

The WLD system works with zones, where each cable, installed even after construction or equipment setup, creates a conductive liquid monitoring zone.

WLD zone(s)

With such a zone, which could be up to 185 meters away from the monitoring device, one could create an effective detection situation by placing the sensing cable right next to the water sources in any type of site, be it a data center, industrial or manufacturing facility, or a warehouse.

With the much faster response to any water presence, this could mean preventing a disaster rather than arriving on site when the damage is already skyrocketing. With the WLD system, what you're buying is time and robust, easy installation within any existing infrastructure.

Let's take a look at some of the most popular sensor and detector options used by professionals for environmental monitoring.

- The sensors are connected to the RJ11 (1-Wire) or RJ45 (RS-485) port. The sensors provide a continuous value of, for example, -23.4°C or 32.7% RH. Device monitoring (SensDesk Portal) can monitor the safe range of values and send an email or SMS alert if the value changes outside the range. You can only use sensors from the HW group.
- Converters and Expanders allow you to connect other types of buses or interfaces to standard monitoring HW group devices. Converters use a continuous value (0-10V / 4-20 mA) as input.
- The Detectors you connect to a DI input (green connector) provide a value of 0/1. A typical example is a smoke detector with a relay output or a door opening detector (door open/closed). The monitoring device (SensDesk Portal) can monitor the switching to the alarm value and send an e-mail or SMS alarm. 
Detector in this definition is a global product. You can connect detectors with relay output from any manufacturer to the DI input of any HW group' device.

60m for RJ11 (1-Wire) / 1000m for RS-485

When talking about sensors, there are two widespread options available from HWgroup, with a significant difference: RJ11 (1-Wire), which allows a maximum distance of 60 meters per RJ11 port between the sensor and the device. The RS-485 standard, which allows a maximum distance of 1000 meters.

This particular difference between these two types of standards makes RS-485 a perfect candidate for industrial-scale monitoring projects, while the fully auto-detecting RJ11 option is better suited for smaller projects such as data centers or warehouses.

Temperature for Cryo / Fridges

Temperature sensors, based on 1-Wire or RS-485, are needed in many niches where it is necessary to monitor precise environmental conditions: cryo storage for pharmaceutical use, refrigerator temperature in shops and warehouses, and many, many more potential applications.

HW group offers special temperature sensors for any application where there are strict requirements for the monitored environment. That's why we produce a RJ11 (1-Wire) based PT100 Frost temperature sensor, specially designed for those situations where an accurate value in the range of -200°C to +160°C needs to be monitored.

Temperature sensor with flat cable for easy installation

The Temp-1Wire-Flat is a unique temperature sensor designed for use in refrigerators. Special flat cable allows it to be bent around a refrigerator and fixed in the doors. There is no need to drill the refrigerator housing and the installation is quite easy and quick. Cable is designed for 1000 cycles of opening and closing of refrigerator doors.

Outdoor / Indoor Temperature & Humidity combined sensors

In addition, HW group produces a wide variety of outdoor and indoor combined sensors, where the customer can have up to 4 sensor values in one package - as is the case with our THPVoC sensor, which provides 4 monitored values in one slick package: Temperature, Relative Humidity, Barometric Pressure and VOC (Volatile Organic Compounds). This is the best possible combination when you need a small but versatile indoor sensor package.

Outdoor relative humidity sensor

With our outdoor sensors, such as the HTemp-1-Wire Outdoor Sensor, you can measure both temperature and relative humidity at the same time without worrying about outdoor conditions. This sensor works in the temperature range of -30 to 85°C, which allows it to be used outdoors. In addition, this particular outdoor sensor is useful if you need to calculate the dew point - a value that is very important in some applications, such as vineyard monitoring.

Converters (60V / 0-20mA / 4-20mA)

Converters allow users to connect analog type of probes (sensors) to standard monitoring HW group devices. 

HW group manufactures three different types of converters for use with our devices. The values can be exchanged via LAN or GSM. When the current is out of a specified range, an email or SMS is sent. Can be connected to remote monitoring systems based on SNMP or Modbus/TCP.

60V 1Wire-UNI
Galvanically isolated voltage sensor up to 60VDC with 1Wire-UNI output. Typical applications include measuring the voltage of industrial sensors (0-10V) or battery voltage. Often used to measure 48V power supplies in telecommunications (48V standard). 

High accuracy allows use for 0-10V applications, sensors can be daisy chained using two RJ11 connectors. This converter is powered from the 1Wire-UNI bus or an external power supply.

0-20 mA 1Wire-UNI
Isolated DC current sensor for 1Wire-UNI bus. Sensor for measuring currents in the 0-20mA range. It is typically used to connect an industrial probe with 0/4 to 20mA output - with a discrete power supply (e.g. to measure fuel level in a tank).

Sensors can be daisy-chained using two RJ11 connectors. The converter is bus powered via 1Wire-UNI interface, which means that a maximum of 2 sensors are allowed per active port.

40-20 mA 1Wire-UNI
Isolated DC current sensor for the RJ11 1W-UNI bus. It's a RJ11 powered converter for external 4-20mA probes. It is typically used to connect an industrial probe with 4-20mA interface - 2wire current loop ("sink" type).

It can be daisy chained using two RJ11 connectors. An external 12-30V power supply is recommended with this converter.

Sensor wiring - Daisy chain Box2 / Rack19” sensors

HW group offers the technical possibility to daisy-chain the sensors for longer or more complex installations. Our Box2 and Rack19" sensors can be daisy-chained with a total length of 60 meters from the first connected RJ11 port. This is the reason why, for example, Poseidon2 4002, while having 6 RJ11 ports (up to 16 sensor values), can be daisy-chained.

Sensors calibration features

The USB calibrator helps you to adjust measured values for most of sensors. 

If you want to connect a third party (analog) sensor to HWgroup's device via RJ11, you would need the USB calibrator. For example, a radar distance sensor with 4-20mA analog output. Using the USB calibrator, you can define 4mA = 1m distance and 18mA = 5m distance. The whole ecosystem of the HW group will later display the distance in meters and would no more use the mA values. 

The conversion doesn't have to be linear, there is a matrix for 8 values.

Summary

HW group manufactures a wide range of wired sensors for every possible application. And with the help of the USB calibrator and converter, it is possible to connect almost any other third-party sensor to the HW group monitor. And with daisy-chaining, a large number of sensors can be installed in a project of any size or market specificity.

SMS-GW is a part of the RME (Remote Monitoring Ecosystem)

Delivering the SMS message or making a voice call alerting the customer if there is something wrong at the remote location is the final service HWg provides. And this alert should still work reliably five years from now, regardless of what is installed on the customer's phone. It is an easy to set up system, but reliable in the long run, which is one of the basic values for HW group.

All HW Group products can use SMS-GW for SMS and CallOut alerts. It's cheaper and easier to have a gateway with a SIM card in the company instead of relying on an independent SIM card with monthly fees in each monitoring device with connected sensors.

Both 2G (GSM) and LTE (nowadays it's probably not necessary to explain the difference between wireless broadband standards) SMS gateways, named SMS-GW3 as it is the third version of the gateway from our production, serve the same function - to send an alert in the form of a user/device-defined SMS message or to make a call-out alert - which is basically a call to a target phone number.

SMS-GW3 works seamlessly with all HWg products without any additional software. One SMS-GW3 on the same LAN could be accessible to multiple HWg devices in the company. It provides the SMS sending and CallOut (ringing) functions to several devices simultaneously and pushes alerts through the queue.

The SMS-GW3 device can also be used with the www.SensDesk.com and 3rd party service provider portals. The SensDesk Technology based portals can use SMS-GW3 LTE for alerting, as long as the gateway is accessible to the portal (either through a VPN or a public IP address) - all SMS and CallOut alerts could be handled by the gateway instead of the software Twilio service available to the portal's paid users (SensDesk.com or providers' portals). 

However, both options (SMS-GW unit / SMS alerting from the Portal) have their limitations and advantages. Using gateway unit only can cause a situation, when the monitoring device is turned off (disconnected) - sending a critical alert message or making a call won’t be available. So the combination with the Portal makes alerting even more reliable.

The following features are shared between the 2G and the LTE versions of the gateway:

1) External antenna with a 3m cable
2) Internal memory for outgoing SMS queue: 100 messages
3) SMS/Calls GW for all HWg devices (RME)
4) SMS/Calls GW for any SNMP software
5) SMS/Calls GW for any NAGIOS (plugin by NETWAYS)
6) Open API: SNMP, XML, netGSM (http, SOAP)
7) Supports the "SMS + Ring" function for combined SMS and CallOut notification
8) Mechanical: 76 x 93 x 28 mm, wall-mountable, fits on a DIN rail (optional)

Using SMS-GW from 3rd party SW/HW

3rd party devices (or software) can access the SMS-GW3 using one of three options: 
1) netGSM (SOAP - HTTP POST) 
2) HTTP GET 
3) SNMP Write (sending SMS from any SNMP software)

One of the most convenient features of the SMS-GW3 is that the SMS and CallOut alerts themselves are fully customizable within different monitoring devices that use the SMS-GW3 as a gateway - easy to connect to devices, especially within the HWg ecosystem of products.

One SMS-GW alerts several people

Therefore, there's no need to support several different configurations on the SMS-GW3 device itself - instead, everything is simply managed on different monitoring units with their sets of sensors responsible for monitoring environmental conditions.

In this way, a single SMS-GW3 can be used to send dozens of SMS or CallOut alerts to an unlimited number of recipients. If, in addition to the standard email alerting, you need a faster and, according to some, more reliable option, or just a slightly different means of delivering an alert - SMS-GW3 is here for you, supporting both the newer LTE and the older but still viable 2G.

Common question: Should I buy a cheaper 2G (GSM) or LTE version?
The very old GSM (2G) standard started in the nineties and is still working in many countries, but most of the national regulators have already declared the date when the 2G GSM cellular network will be switched off. Switzerland will probably be the first European country to switch off its 2G coverage. 

However, there are so many devices that depend on this network that it may take a decade for this to happen in your country.

Summary

Using a single hardware SMS-GW unit to send alerts (SMS/Call) from multiple LAN sensors in the enterprise makes the entire HWg monitoring system more robust & long-term reliable, even in a cost-effective and fully offline (without portal) version.

The product we sell to our customers in the HW group is the delivered alert message, not an alerting device or sensor. Therefore, we want to warn our customers even in moments when the external environment (power or connectivity) is not working as usual.

To provide long-term reliable monitoring system, we offer "Device Disconnected Alert" feature even in the free version of the SensDesk Technology based portal - www.HWg-cloud.com.

Alarm situations:

1) Measured sensor value is higher/lower than defined limit. 
This is a standard alert. 

2) Measured sensor disconnected (e.g. torn off the connected port). 
It's standard alerting. 

3) The monitoring device to which the sensor is connected has no power. 
It's a device disconnected alert. 

4) The monitoring device does not have an Internet connection. 
It's a Device Disconnected alert.

All in all, it's a pretty good protection of the environmental situation at your remote site. To achieve easy-to-use, long-term reliable monitoring, we use the Protal, because scenarios (3) and (4) can't be realized without a higher level system.

What happens if one or more of the sensors connected to the monitor are disconnected, torn off, or damaged in any way that prevents them from operating normally?

Standard alerting from the device

It can be done with the Portal, but also from the monitoring device such as Poseidon2 or STE2.

You'll see something like this in the device interface:

For the (2) Sensor disconnected scenario, you can also define an alert, -999.9 degrees Celsius means sensor not found and the device can alert you of this situation.

Email alert from the device must be converted to email. Feel free to use your company SMTP server, but HW group would like to warn you against using public SMTP servers. We have an article about why it's not a good idea (not long-term reliable): https://www.hw-group.com/support/use-a-public-smtp-server-not-recommended

We recommend using the Portal. Even for free, HWg-cloud.com can provide you with much better service than SMTP servers from Google or Yahoo, for example.

Standard alerting from the Portal

In the portal, you can also see graphs of the values over time. If you get a "Sensor Invalid" state:

This is different from the temperature alert and could be sent to the recipient as a different type of alert message. It indicates sensor failure rather than temperature fluctuation, which is more accurate and correct in this case.

A cable could be accidentally pulled or damaged in some way, preventing the sensor from sending the monitored value to the monitoring device. And the alarm receiver could distinguish such a situation from a true temperature alarm. The former indicates a sensor malfunction, the latter a change in the monitored environment.

Portal reaction to disconnected device

What happened there? There is really no way to know. It could be the entire monitored facility that went down, or just the specific power distribution unit, or a specific plug that "fell out of the socket". Things happen. You just need to know what exactly happened so you can take appropriate action.

If the HWg monitoring device loses power, the portal - in this case HWg-cloud.com - will display the following message:

How fast do I get information that the device is not connected?

In the case of the HWg-cloud.com service, it takes less than an hour to definitively determine that the device itself is not working properly, thus changing the device status in the account:

And trigger an alert sent directly from the portal. Understandably, if the power goes out - no SMTP destination would be able to receive an alert because it couldn't be sent. When the device comes back on, its status in the portal changes within a minute of the initial data push.

Disconnected devices on the sensor graph:

Device invalid icon in the daily graph, followed by a continuation of the monitored value with another Device invalid icon (and a possible alert) at the end.

Summary

Using SMTP server to send e-mail alerts from the device is a common way. Better than using public SMTP server is to use the Portal service from HW group, it's more long-term reliable and free of charge service. Above shown graphs of values, and a central place to manage email alerts is yet another bonus you get besides the device disconnected alert. It's an alert that is sent the moment the monitoring device (STE2, Poseidon, Ares, ..) is turned off or disconnected from the network.

The portal service monitors if the monitoring device is connected & working properly. It increases the reliability of the entire Remote Monitoring Ecosystem.

Different Philosophy of Water Detection - Water Leak Detection Sensor Cable

There are 2 ways of water detection that we use in HW group for remote site monitoring:

1) SPOT Water Detection;

2) WLD (Water Leak Detection) with the sensing cable.

The SPOT water detection is much, much cheaper from a sensor point of view, but the physical environment should be adjusted to deliver water in minimum volume to the water detection sensor. The physical environment adjustment is typically much more expensive than the sensor itself. 

The WLD (Water Leak Detection) with sensing cable uses the sensing cable placed at locations where you first expect the water. Water (liquid) is detected along the entire length of the WLD sensing cable. It's more expensive from the sensor’s price perspective, but you can detect really few drops of water in real installations. 

Yes, we are talking about a 20x higher price from the installation cost point of view, but time is critical in these applications. Are you paying for early water detection (within 15 minutes) or swimming invitation (within 15 hours)?

Experience from real installations

There are several water detection sensing cables on the market. The problem is to choose a system that is suitable not for long pipelines, but for real buildings:

a) Sensing cables with a bend limit must be installed under all other cables in the building and well fastened to the ground. It's hard to guarantee this with an external installation company. 
b) Finding a water spot based on distance of detection on the sensor cable is a great feature for the pipes, but not for the buildings. There is zone system much easier to understand in the real installation. 
c) Some sensing cables use capacitive detection and use non-insulated wires as part of the sensing cables. It's a significant limitation factor for installations on the metal floors.
d) Sometimes you need to extend the water sensing cable with non-sensing cable. And you need to realize when on site, not based on the prepared project. Easy to cut/extend non-sensing cable offers great help in these scenarios.

HWg WLD sensing cable

HW group's WLD (Water Leak Detection) Type A sensing cable is a three-state sensor designed to detect any conductive liquid along its surface. 

The maximum length of a WLD zone is 185 meters of sensing cable. The liquid is detected along the entire length of the WLD sensing cable. This means that the entire zone (area) is monitored at one time as an entire area. We can't say at which exact point (distance) of the cable the water was detected, but we are able to detect water quickly and reliably.

It is recommended that multiple WLD zones be used to detect water stains, even within the same room.

Each WLD zone reports 3 states to the monitoring unit:

- 0 = Not flooded
- 1 = Flooded
- 2 = Disconnected

This means that you will also know if something happens to the cable that maintains the monitored zone. Since our sensing cable is robust and can be installed in a variety of ways due to its characteristics, we want to be sure that the operator knows not only if water is detected, but also if something happens to the cable itself.

The WLD sensing cable from HW group has several unique features

• No Bend Limit

Unlike many water detection cables, the WLD sensing cable doesn't have a bend radius limit. It can be knotted and still work, which means installation is easy and doesn't require special training. HW group's WLD sensing cable can be installed with the other cables in the cabling system. This can save you a lot of money during installation. 
No bend limit for the WLD sensing cable also means no cable movement would cause false alarms.

• No Grip Limit

Point pressure within a reasonable range won't change the functionality of the cable. You can step or press on the cable without triggering an alarm. It could be routed even over the door sill.

• No Twist Limit

Like any other electrical cable, the WLD sensing cable can be twisted. No twist limit for the WLD sensing cable also means that no cable movement after installation would cause a false alarm.

• No Reuse Limit

After the liquid is detected and hopefully stopped from flooding the monitored facility, the cable simply dries out and resumes its primary function.

WLD Project Design

The WLD sensing cable makes it possible to implement a surface water detection monitoring system, not just spot detection. One or two spot detectors are not enough to monitor a large area, while with the sensing cable and various WLD devices you can create as many zones as you want - real world scenarios in larger facilities could have up to 50 separate zones with the cable installed around the entire perimeter of a room or any other given space.

Yes, the WLD sensing cable is more expensive compared to spot-detector based leak monitoring, but it's also much faster and more reliable in delivering the alarm when the water is present - it's a 15-minute reaction alarm instead of hours of waiting for the two contacts on the detector to be properly flooded along with everything else on the floor.

With the simple and quick installation and long-term reliability of the WLD system and its components, the combination of sensing cable with non-sensing cable segments ultimately makes it a cost-effective solution for those organizations where early detection of just a few drops of liquid could mean saving the entire business.

Summary

The WLD (Water Leak Detection) system is based on the WLD sensing cable type A for detection. The whole WLD system consists of different products (with WLD zone inputs) aimed at different usage scenarios - from smaller installations to the really huge ones. Sites with LAN / WiFi or with LTE / NB-IoT connectivity. But as the heart of any WLD system, the WLD sensing cable connected to the WLD zone connector is its most critical part.

At HW group, we are focused on providing long-term reliable service to our customers. If you use our monitoring device for a temperature alarm, it must work now and in 2 / 5 / 8 years without touching it. Through our support requests, we see that a significant percentage of our customers repeat the same mistake again, and we would like to offer a solution.

HW group has several intentions when designing remote monitoring solutions:

1. All our products must be installed by experienced IT professionals within 1 hour;
2. We do our best to provide long-term stable service without false alarms;
3. We maintain compatibility in the terminology of our hardware, interfaces and concepts.

Many customers ask for very basic functionality: an email alert when there is a temperature problem at the remote site. Yes, it can be upgraded to SMS alerts, repeated, escalated, but it's all beyond the basic functionality of simple email alerts.

Since the beginning of the Internet, SMTP (Simple Mail Transfer Protocol) was the easy-to-use service for this kind of purpose. We all learned in the 90's to simply send the email alert from the device to the SMTP server and that was it.

If you are inside corporate network, sending alert emails via SMTP server is still a valid idea. You know your SMTP server, someone is responsible for its maintenance.

But if you are using for sending alert emails through the public SMTP server like those listed below, you should change your mindset. Since the 90's there is one big game changer: SPAM.

Public SMTP servers we have tested:

• Gmail.com
• Office365.com
• Outlook.com
• Hotmail.com
• smtp-mail.outlook.com
• GMX.com
• GMX.de
• Yahoo.com
• Seznam.cz
• Centrum.cz

These SMTP servers work most of the time for sending alert emails, but it is not a long-term reliable solution. Which is why we offer you more reliable option free of charge.

The 90s are over, let's update our approach to long-term reliable alerting

In the ever-evolving landscape of technology, the passage of time often casts a revealing light on the methods and tools we once relied upon. Twenty or so years ago, the concept of sending alerts via a public SMTP server represented a reliable communications frontier. Today, in 2023, it stands as a testament to the transformation of real-time communications and the emergence of superior alternatives.

Nineties were fine and fun, but long gone

Using public SMTP servers is unreliable in the long run

The rapid expansion of networks has increased the amount of data flowing around the world, changing our habits, our experiences, our lives. Not surprisingly, the protocols at the heart of the technologies we use every day have evolved as well.

In the late 90s and early 00s, sending an alert email through a public SMTP server (such as gmail.com or GMX.com) was one of the few ways to send email from a remote device. Today, email alerting would probably be just one of many alerting options, but it's still very popular in the IT community. However, the fact that the embedded device sends email through the public SMTP server does not guarantee that it will be delivered to your mailbox. The fact that you tested it by pressing the "send test email" button on the remote monitoring device's website and it worked today does not guarantee that it will be delivered tomorrow, or in one or three years! And we are talking about early email alert that protects temperature conditions on your remote site, environment in the technology room of the company or institution of your paying customer.

To be clear, we are only talking about public (free) SMTP servers. It's reasonable to use your own private SMTP server within your company. You know about server updates, you can use whitelists and so on. This is not the case with public mail servers.

Why it's not a good idea to use free SMTP servers for alerting?

Free SMTP servers are dedicated for standalone client, smartphone client and for daily use of this service. It's not dedicated for embedded thermometer to have an active user account for 5 years without sending an email and then bulking 10 emails within an hour. Of course, the SPAM protection in these services will identify your email alerts as spam activity and will ignore your emails.

Why is it a bad idea to use public SMTP servers in 2023?

• SPAM issues: Public SMTP servers are constantly improving their protection against SPAM messages. Your personal computer, laptop or smartphone doesn't have a problem with this, but a 3-15 year old thermometer is another story.
• Deliverability issues: Due to strict email authentication requirements (such as SPF, DKIM, and DMARC), misconfigured email servers can cause emails to be marked as spam or rejected altogether. This can prevent legitimate email from reaching its intended recipients.
• Blacklisting: Email servers and IP addresses can end up on email blacklists for a variety of reasons, such as sending too much spam or experiencing security breaches. Being blacklisted can result in email delivery failures.
• Server downtime: Email servers can go down for maintenance, hardware failures, or cyber attacks. During these times, email delivery can be delayed or interrupted.
• Limited encryption: Although SMTP supports encryption (SMTPS and STARTTLS), not all email servers and clients implement it properly. This leaves email content vulnerable to interception in transit.
• Full inbox: Have you ever run out of space on the public email service? Haven't yet?
• Overreliance on email: In an era of instant messaging, collaboration tools, and remote monitoring centers, organizations and individuals may rely less on email for critical communications, reducing the urgency to address its reliability issues.

Email popular and easy to use alerting option. But the long-term reliability of free SMTP servers is not the same today as it was in the past. The truth is that public SMTP servers and services have gone through a huge, transitional change over the past two decades. And encryption has been a big part of that change, as we're now moving into a world of mostly encrypted communications.

Take a look at this timeline:

• SSL 1.0 (1994): The first version of SSL was never released to the public due to security vulnerabilities.
• SSL 2.0 (1995): The first public release of SSL, but it had significant security flaws. It introduced the concept of a secure handshake and encryption of data in transit.
• SSL 3.0 (1996): SSL 3.0 addressed the vulnerabilities in SSL 2.0 and became widely used to secure Web communications.
• TLS 1.0 (1999): Transport Layer Security (TLS) was introduced as an upgrade to SSL 3.0 to address vulnerabilities and improve security. TLS 1.0 maintained compatibility with SSL 3.0.
• TLS 1.1 (2006): TLS 1.1 included security enhancements such as protection against Cipher Block Chaining (CBC) attacks and more secure hash functions.
• TLS 1.2 (2008): TLS 1.2 further enhanced security by introducing support for advanced encryption algorithms, including AES-GCM and SHA-256.
• TLS 1.3 (2018): TLS 1.3 is the latest and greatest standard for securing Internet communications. It brings significant improvements in security, performance, and reduced latency. Notable features include faster handshakes, elimination of insecure cryptographic algorithms, and perfect forward secrecy.

With any of these developments in encryption technology, you would probably need to make sure that the alerting device is still connected to the public SMTP service provider. And we're not talking about captchas and other human verification methods that add another layer of complication. 

Another major change was the introduction of a separate username and password for the SMTP client that is different from the end-user username and password. This further complicates the device's integration with the public SMTP server, making it more difficult for an ordinary user to get the system to work reliably in such a configuration. And having to check a hidden box somewhere to continue using an embedded system is not the answer.

Easy to use & long-term reliable solution?

Long-term reliable email alerting is a critical part for 20-50% of HW Group customers. To provide you with "only" our own SMTP server will be very limited solution.

We have a better solution for you with device invalid (disconnected) alerts, graphs and one place to manage all alerts: Portal. In free version for up to 20 devices connected to one user account: www.HWg-cloud.com.

Providing a long-term reliable solution is exactly why HW group develops the SensDesk technology portal. To give HWg customers a long lasting approach to send a mission critical alert and assure the user that the message has been sent.

Of course, it means that you have to learn the portal features, accept that it will take you another 15 minutes, +15 minutes to learn how to set it up and work with it.

Email alerts from the portal (considering the free HWg-cloud.com):

1) User is notified when the sensor goes above or below the user-defined safe range.
2) User will be notified in one hour if the monitoring device is disconnected (Internet or power outage).
3) All emails are managed in one place. It's easier to update email addresses when someone leaves the company and email needs to be updated.

Is this really free?

Yes, email alerting, device invalid alert and 10 days history with graph are free at www.HWg-cloud.com. HWg provide this as a service for their devices.

Only for longer history, SMS alerts, PDF reports and other services you will need to pay for the portal, either www.SensDesk.com or solutions from local portal providers.

What is RME (Remote Monitoring Ecosystem)?

In HWg we provide much more than just the email alerting monitoring device. Even with the cheapest STE2 LITE device you can use the whole ecosystem of our RME services:

• SMS-Gateway for SMS and voice call alerts
• UPS for power backup
• HWg-cloud for free or paid SensDesk subscription
• XML and SNMP API
• HWg Monitor application

Summary

Do not rely too heavily on the public SMTP server, especially for mission-critical alerts. The 90s are over. Yes, you can save 30 minutes and rely on a free SMTP mail service. 

But every single SPAM protection measure implemented by this free service will probably disable your email alerts and you won't get any notification about it.

Use HW Group's portal service. It's free and much more reliable in the long run. The HWg-cloud.com or the paid SensDesk.com portals. Both would save your time and effort and eliminate the loss if the alert isn't delivered on time.

4 simple reasons to use HWg-cloud free Portal: