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Poseidon2 3468: IP thermostat with 230V/16A-rated relay outputs

IP unit for remote monitoring, web thermostat, industrial-telco version. Supports external RJ11 sensors (voltage, current, illumination, humidity), 4x digital dry contact input and 2x 110/230V relay output. Supports e-mail alerts, SNMPv3, Modbus/TCP, XML, and the online portal.

Poseidon2 3468 is designed for telco or industrial applications. Based on external sensor readings, Poseidon2 3468 sends alerts or activates relay outputs. Output relays can directly switch 110/230VAC. The product is CE compliant.

Sends an e-mail or SNMP Trap whenever a sensor value exceeds the specified range. Minimum duration condition can be set for alerts to closed contacts (activated digital inputs). For example, “send an e-mail if the door is open for longer than 120 seconds”.

Relay outputs can be controlled remotely over the Web, or using M2M protocols (XML, SNMP, Modbus/TCP).

A typical application is an “IP thermostat” or “hygrostat” (humidity controller). The relays control heating or cooling using an external temperature probe, humidity probe (hygrometer) or other sensor.

  • 2x 110/230VAC 16A double-throw relay contact

  • Connect up to 8 external sensors of various quantities.
    Converters for 0-60V, 4-20mA, Pt100 or Pt1000 temperature probes, illumination sensors, flood detection in a 2D area, temperature, humidity, 0–30A AC, and so on..

  • The unit can be powered by 9–30V and it can also be powered by -48V (Telco standard).

IP thermostat Poseidon2 3468

DIN rail    Rear view    Side view   

Poseidon2 3468 Tset

HWg-SMS-GW for sending SMS


  • Ethernet: RJ45 (10/100 BASE-T)
  • WEB: Built-in web server
  • Logging of values: Over 250,000 records (internal Flash)
  • Sensors: 2xRJ11 – max. 8 external sensors (1-Wire / 1-Wire UNI)
    Can measure: humidity, voltage, current, 4-20mA, illumination, temperature (incl. Pt100, Pt1000) and many other quantities...
  • Digital Inputs (DI): 4x DI for dry contacts (state detectors)
  • Digital Outputs (DO): 2x DO relay outputs (250V / 16A)
  • Power: 9–30VDC or –48VDC (Telco standard)
  • Mechanical: Fits on a DIN rail, 145 x 90 x 40 [mm]
  • M2M communication protocols: SNMP (version 1 & 3), XML, Modbus/TCP, HWg-Push
  • Sending text messages (SMS): Alerts can be sent as text messages (SMS) via a remote HWg-SMS-GW over the network. No software is needed.
  • Built-in local functions: Output control according to external sensor reading or a digital input (“thermostat” mode)
  • Warranty: 2 years
  • Support for programmers: HWg-SDK
  • Recommended online portal: – free online portal
  • Supported software
    • HWg-Trigger: Control of other IP devices, alarm redirection to SMS
    • HWg-PDMS: Logging, export to MS Excel, reports
    • Third-party software (SCADA systems, Modbus/TCP)

Usage examples

  • Remote thermostat / cabinet monitoring
    Monitor doors, power supply status, temperature / humidity, dry contacts.
    Can be used for environment control or remote restart.

  • Industrial applications
    Remote monitoring of dry contacts, 4-20mA probes or Pt100 / Pt1000 temperature probes.
    Values are logged to the internal memory.

  • Monitoring at –48V telco nodes
    Poseidon2 3468 and its sensors can be powered by –48V DC.
    It is possible to power the unit from a protected DC part and monitor a problem-prone AC part.

  • Monitoring of power supply, back-up generators or UPS Fuel level, diesel generator status, remote start over IP, monitoring of temperature and service interface (Dry contacts).

  • Pharmaceuticals and food storage– temperature logging
    Monitoring of storage conditions – warehouses, cooling plants, freezers, refrigerators.
    Application software can create HACCP reports.
  • Smart buildings
    Sensor readings can be shared in several applications.

  • Information booths (terminals), ATM's
  • IP surveillance systems
  • Remote gate control

IP thermostat and remote environment monitoring

IP thermostat and remote environment monitoring
  • Temperature and humidity monitoring inside a cabinet.
  • Fits on a DIN rail.
  • Can be powered by –48V DC, provides 12VDC for powering sensors.
  • E-mail or SMS alert when a value is exceeded.
  • Relay activation (heating / cooling) according to sensor readings.
  • Connection to a NMS (SNMP monitoring) or SCADA (Modbus/TCP) system.
  • Door contact alerts to open doors.
  • Temperature and other values are logged to the internal memory.
  • Thermostat (hygrostat) can be configured over a web interface.

Extending the number of digital inputs, sensor daisy-chaining, relay outputs

Extending the number of digital inputs, sensor daisy-chaining, relay outputs
  • Four dry contacts can be connected to Poseidon2 3468 digital inputs.
  • Number of dry contact inputs can be expanded with Expander 4xDI 1W-UNI. The expansion module connects to RJ11 as a sensor and counts as four sensors.
  • There is an internal logger for all sensors and Digital Inputs.
  • The device can be powered by -48V DC in Telco applications.
  • Sensors connected to RJ11 (1-Wire UNI) can be daisy-chained.
  • To connect the sensors, use the two RJ11 jacks on the sensors, or an external T-Box unit.

Connecting powered 4-20mA probes or Pt-100 / Pt-1000 temperature probes

Connecting powered 4-20mA probes or Pt-100 / Pt-1000 temperature probes
  • A converter for two Pt-100 or Pt-1000 temperature probes can be connected to the Poseidon2 monitoring unit.
    The converter supports 2-wire, 3-wire and 4-wire connection of resistive temperature probes.
  • Industrial sensors with the 4–20mA interface can be connected to RJ11 using a converter. The external sensor is electrically isolated.
  • The external 4-20mA probe is powered from the measuring loop. The white converter box is powered from 12VDC (PowerOut output). The converter includes an electrically-isolated current supply for the external 4-20mA probe, providing up to 24V.
  • Converters for connecting external sensors can be calibrated using a curve with 8 points.
  • Other converters that can be connected to Poseidon2 3468 over RJ11: 0-60V DC, 0-30 AC, 0-20mA DC, 0-80A DC and more..
  • All values are stored into the internal flash memory logger.


Sensors (most popular)

Expander 4xDI 1W-UNI

4x DI (dry contact input) to RJ11

  • RJ11 1-Wire UNI (needs 4 positions)
  • Designed for indoor use

HWg-WLD Relay

Detects flood in a 2D area using a cable

  • RJ11 1-Wire UNI (includes power)
  • Supplied with 2m detection WLD cable

Sensor 60V 1W-UNI

Measures voltage, 0–60VDC

  • Electrically isolated
  • Recommended for measuring –48VDC

30A Current probe 1W-UNI

0–30A AC current sensor for indirect measurement

  • 0-30A current measurement using a split-core transducer
  • Installation without disconnecting the measured circuit

Sensor Light 1W-UNI 3m

Illumination intensity sensor with a 3m cable

  • Indoor use
  • Output 0–100%

4-20mA 1W-UNI sensor

Measures 4–20mA DC current

  • Electrically isolated
  • Power for an external 4-20mA probe

HTemp-1Wire Outdoor 3m

Temperature + humidity (outdoor)

  • –30 to +85°C (–22 to 185 °F) 
  • 0–100% RH   (Relative Humidity)

HTemp-1Wire 3m

Temperature + humidity (indoor)

  • –30 to +80°C (–22 to 185 °F) 
  • 0-100% RH   (Relative Humidity)

Temp-1Wire-Flat 3m

Temperature (in coolers and freezers).

  • –30 to +60°C (–22 to 185 °F) 
  • IP67, 17240 stainless steel probe – Ø5.7mm
  • Flat cable for installation in a cooler

Humid-1Wire 1m
Humid-1Wire 3m
Humid-1Wire 10m

Humidity (indoor)

  • 0-100% RH   (Relative Humidity)


Temperature + humidity (1U size for 19" rack mount)

  • –10 to +80°C (14 to 175 °F)
  • 0-100% RH   (Relative Humidity)

Temp-1Wire 1m IP67
Temp-1Wire 3m IP67
Temp-1Wire 10m IP67

Temperature (indoor & outdoor)

  • –10 to +80°C (14 to 175 °F) 

>> Sensors overview

Detectors (most popular)

FDR26 Smoke Detector

Smoke detector (12VDC power, relay output)

Door Contact

Open door detector

Impaq shock sensor

Vibration detector (12VDC power, relay output)

Gas Leak Detector

Detector of flammable gases (12V, relay output)


Power failure detector (relay output)

Motion PIR detector

Motion detector (12VDC power supply)

>> Overview of all sensors and detectors

Software and applications

    HWg-PDMS: Cabinet temperature monitoring system
  • Configuration: UDP Config  – Configuring the IP address
  • Monitoring and logging: HWg-PDMS – Monitoring software with MS Excel reporting
  • Online service for remote monitoring:

  • Mobile phone app: iPhone, Android and more..
  • Third-party software: SNMP (Nagios, Cacti, Zabbix, The Dude, Paessler PRTG, OpenNMS, HP OpenView, IBM Tivoli, Axence nVision, Ipswitch WhatsUp, CA NSM, SNMPc and more.. )
  • For programmers: HWg-SDK contains interface descriptions and examples of using M2M protocols in several programming languages
    (JAVA, PHP, Borland C++ Builder 6.0, Microsoft Visual C++ 6.0, Borland Delphi 6.0, Microsoft Visual Basic & Excel VBA, VB.NET, C code for Linux, JavaScript (AJAX) Microsoft Visual C# 2005 (.NET))

>> Software and applications

Connection to the online portal

  • Poseidon2 3468 can be connected to the online portal.
  • All devices, sensors, values, history and charts can be viewed from anywhere over the web, or in a mobile app.
  • For programmers: Devices connected to the can be monitored using a XML interface.

Text message (SMS) alerts

Alert SMS can be sent from the Poseidon2 3468 monitoring unit in several ways:

  • Directly over the network using SMS-GW
    A text message can be sent from the Poseidon2 3468 unit to a specified phone number using the “HWg-SMS-GW” unit.
    No software is needed. HWg-SMS-GW should be connected to the same LAN. Sender's phone number is defined by the SIM inserted in the HWg-SMS-GW unit. Recipient's phone number is configured in the Poseidon2 3468 unit, similarly to e-mail recipients.
    One HWg-SMS-GW gateway can be shared by several devices (e.g. Poseidon2 4002 in the picture).
  • With the HWg-Trigger application for Windows
    The HWg-Trigger application runs in the background on any PC with MS Windows. The application checks for device failures, disconnected sensors, or sensor readings outside of the Safe Range. Alarm status can be notified e.g. by sending a SMS to a specified number using a “HWg-SMS-GW” in the same LAN.
  • With third-party software applications
    Many SCADA (e.g. CapTemp) or SNMP (Nagios, Zabbix, ..) applications can monitor the status of Poseidon2 3468 units and send alerts via SMS.

Special functions

IP relay control (Internet thermostat) – Local conditions and output control

Each DO (relay output) can be controlled in several ways:

  • Manually over the WWW interface
  • M2M XML protocol
  • M2M Modbus/TCP protocol
  • M2M SNMP protocol (not recommended for controlling the outputs for security reasons)
  • Local condition (IP Thermostat function)

    Relay output is activated when a specified condition is true (sensor reading higher than/equal to/less than a certain value). The condition can be tied to any sensor or digital input. The relay output then works as a web enabled thermostat or hygrostat. The hysteresis value configured for individual sensors is used.

Logging of values

  • Poseidon2 includes an internal flash memory for logging of values. Data are kept even if the power goes off.
  • The logger has a capacity for 250,000 records. For Poseidon2 3468 working as a temperature logger with one temperature sensor and 4x DI, this means enough memory for 230 days (7.5 months) when logging every 300 [s] (5 minutes).

Tip: The HWg-PDMS application can, for instance, read data from the internal memory over e-mail or web interface.

Frequently Asked Questions

    Ask for the price or details:
     - Web:  http://
    Country: *

    Spam protection. How many is SIX times six?

  • What is the lead time for ordered samples?
    We keep Poseidon2 3468 units in stock, samples are shipped within 24 to 48 hours.
    When your order is confirmed, we inform you by e-mail about the approximate delivery date.
  • You mention 48V power but also 9–30V. What is correct?
    Poseidon2 3468 has two power supply inputs. It is possible to use either the –48VDC telco standard, or the usual range. In both cases, the +12V output can be used to power the sensors (e.g. the smoke detector).
  • Can I control a relay output with a sensor? For example, turn on A/C if the temperature exceeds 35°C?
    Yes, the output can be controlled with a "local condition". We call this the “Thermostat mode”. It is configured on the “Outputs” tab, including the thresholds (e.g. 35°C) and the sensor.
  • How can I create a graph or protocol with recorded temperatures?
    Use the supplied HWg-PDMS software. Values recorded in the database can be displayed or exported to MS Excel.
  • Do you offer a SW solution that will alert me to an outage of a Poseidon2 unit?
    Yes, you can use the HWg-Trigger application that runs on any Windows PC.
    Another option is the online service – free portal for IP sensors.
  • What is the maximum number of e-mail recipients for alerts?
    Poseidon2 itself can send e-mails to 5 e-mail addresses at the most.
    With the online service or the HWg-Trigger application for Windows, e-mails alerting to OK/Alarm states can be sent to more than 5 e-mail addresses.
  • Can I use the product as a web relay for 230V – switch a relay over IP?
    Yes, the relay output of a Poseidon2 3468 can be controlled over IP using M2M protocols (Modbus/TCP, SNMP, HTTP/XML and more), acting as an IP relay for 110V or 230V.
  • What is the warranty?
    The standard warranty is 2 years, can be extended upon request.
  • Where can I find the prices of your devices?
    Ask our distributors, or request a quote from us (by e-mail or by filling out this form).

>> Online order form




Product Description
Poseidon2 3468 Tset Poseidon2 3468 quick start set with a temperature sensor.
Contains the Poseidon2 3268 unit, a power adapter, a temperature sensor (3m cable), a CD and a manual. (photo)
Poseidon2 3468 Poseidon2 3468 unit only.
Remote monitoring for industrial and telco applications. Fits on a DIN rail, can be powered by -48VDC, 4x DI , 2x DO 230V/16A, 2xRJ11 – max 8 sensors (1-Wire UNI). WEB, XML, SNMP, Modbus/TCP.
HWg-SMS-GW2 Central SMS Gateway - start set
GSM SMS gateway for sending text messages from other HW group devices over the LAN. Includes an internal GSM modem, an external antenna with 3m cable, a power adapter and a CD. - photo


Poseidon accessories


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IP thermostat, web enabled thermostat, IP relay 110V, web relay 230V, remote thermostat, internet thermostat, temperature logger, hygrometer, powered by -48V DC,  

modbus relay, SNMPv3, snmp relay, humidity controller, Ethernet relays, snmp thermostat, humidity control, remote control thermostat, thermohygrometer, IP-relay, Modbus/tcp sensor, DIN ethernet relay, pt100, 4-20mA, pt1000

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