SD 4-20mA: AI (Analog Input) to the portal (LAN and WiFi)

The SD-4-20mA is remote monitoring unit with 1x AI (Analog Input) for external 4-20mA / 0-20mA probe. External 4-20mA probe is powered from the device.

The device is powered by an external power supply of 5V or from PoE. The LAN connectivity can be provided by Ethernet or WiFi.

The SD-4-20mA is IoT monitoring kind of product from HW group. It means it have to be connected to the portal (SensDesk Technology based).

  • Default portal service is (free of charge portal by manufacturer, up to 20 devices per user account).
    Device can be migrated to any other SensDesk Technology portal (even on premise installation on the local network).
  • is paid portal service option from HW group.
  • Portal Providers is list of other online portals available by HW group partners.
  • Analog Input can be reconfigured from 4-20 mA (default) to 0-20 mA
  • Connectivity: Ethernet and WiFi
  • Power: External adaptor 5V / PoE
  • Simple installation: DHCP, enabled
  • Embedded WEB server (WiFi setup, current loop 4-20 mA configuration)
  • Fast & simple installation on the site “just click & go”
  • Portal for device management required ( as default)
  • Free portal service ( for up to 20 devices available
  • Paid portal services available (any SensDesk Technology portal)
  • Metal housing, DIN and rack mount available
Applications and usage: 
  • AI (Analog Input) to connect special industrial analog probes (sensor) to the portal
  • Connecting 4-20mA probe for: Liquid level monitoring in Diesel/Water tanks
  • Connecting 4-20mA probe for: Water pH / pressure / level probes
  • Industrial applications

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AI (Analog Input) for common industrial analog probes (sensors)

AI (Analog Input) with 4-20 mA is most popular interface for external industrial probes (sensors). Many industrial probes with the 4-20mA (0-20mA) analog interface can be found on public market. The SD-4-20mA IoT Monitoring device is kind of “converter” to connect measured analog value to the (SensDesk Technology based) portal.

Converted calibration

Each AI (Analog Input) have to be adjusted (configured) together with connected probe. It's one sensor unit together with the probe only. Conversion curve, measurement units and external probe parameters should be configured locally before the SD 4-20mA device with connected external probe is sent to the site.


HWg Video Flyer about SD 4-20mA

User benefits

  • Device installation is fast & easy even for “Junior users”.
  • Power for 4-20 current loop is provided by the SD-4-20mA (device is powered from external power 5V or from PoE).
  • Portal can alert the user by email if the 4-20mA probe is disconnected.
  • The HWg Monitor mobile App can show you all sensor values in your portal account
  • Portal can alert users when the device is not powered or there is cable failure.
  • SMS, Voice call alerts or PDF reports can be used with paid portal services.

Usage scheme

SD-4-20mA is IoT monitoring unit with one AI (Analog Input) for external 4-20mA / 0-20mA probes.


Portal is required 

All SensDesk Technology logoIoT Monitoring Devices have to be connected to any SensDesk Technology-based portal (SaaS) in order to work properly.

The SensDesk Technology is a portal solution from the HW group to manage remote sensors and devices (only for HW group products). Portals offer a central overview of all the values and provide a variable combination of features like sending the alarms, reporting, history records, outputs into the Open API, etc.

There are several portals available. The manufacturer provides and, 3rd party companies provide more than 10 other portals. Users can migrate the device between any available SensDesk Technology portals.

 u Limited & Free portal features - Portal Providers icons

  • the default pre-configured portal option
  • provided by the device manufacturer
  • sends email alerts and offers basic remote device management
  • advanced features of SensDesk Technology are not available
  • You can migrate your devices from to any other SensDesk Technology portal at any time
    Paid portal service with advanced portal features icons

  • Several subscription plan options
  • SMS / Voice call alerts to any mobile phone
  • Graphs / MultiGraphs (data history)
  • PDF reports
  • Email alerts/alarm escalation
  • History log
  • Open API: All sensor values are available via XML / SNMP protocols



Local portals by Portal providersSensDesk Technology portal features - Portal Providers icons 

  • portals based on SensDesk Technology ran by 3rd party providers
  • local languages and support
  • various mix of free/paid services
  • various commercial names



Why do you need a portal? 

  • Using the portal makes the IoT monitoring devices easy to install even by junior local staff. To install the IoT devices you don´t need any experts on the site.
  • The portal can then send alerts, provides remote device management. Portal is one place with all your sensors & graphs overview, reporting, Open API, ...
  • Even the default free of charge version of the portal ( can alert you by email when device disconnected / sensor value alarm.
  • Price of the portal service is around 15 % of the hardware cost per year.


All your sensors are in your pocket 24/7Mobile App HWg Monitor icon

You can have a display with all your sensor values in your pocket with you 24/7. Check HWg Monitor mobile app. The app can be running on your phone, on the Android TV, or on the Tablet installed on the wall.


AlertingAlert icon can immediately alert you by SMS or Voice call to your mobile phone in the case of an Alarm situation. If the time is critical, every second counts. The immediate reaction to an alarming situation can be also responded to by closing/opening a remote relay output, which can for example turn on a siren. Quick alerts lower the risk of costly damages in case of an Alarm. Alerts from the portal can escalate to higher intensity or to another person if the problem persists.


Sensor values in MultigraphsMultigraph icon

Multigraphs can display multiple sensor values from different kinds of sensors in one graph. That offers a situation overview of a remote site, significant fluctuance of sensor values is visible at first sight. It is popular for comparing time events. system is also showing sensor value graphs that alert you when the device is not working or any sensor is out of defined limits. 

For an example of working with charts in SensDesk, see the application note.

PDF reportsreport icon

You can easily create comprehensible reports with graphical representations of sensor values in one or in a number of locations. You can create reports in PDF (CSV) periodically. Reports can be printed & clicked to the invoice for your customer. Reports for pharmaceutical / other production (HACCP) are possible.


HistoryHistory icon

Thanks to the history log you can easily compare your historical data.


Open API Open API icon

You can connect the data from to any other system. Portal user account (all connected sensors) is accessible by Open API (SNMP, XML).

  • A list of all the sensors / current values can be downloaded in XML format (HTTP get). 
  • All the values can be read via SNMP v1 / v3 protocol.



The number of Dashboards, Multigraphs and Reports is limited by the subscription plan as well as the length of the history log, check the plans:

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SensDesk Technology

The is an on-line service from the HW group to manage remote sensors and devices. Only the HW group products can be connected. is an on-line service (portal] from the HW group company to operate and manage remote sensors and devices.