Monitoring System 500T - Alarm System including Dry Contacts

Fault alarm system: Central collective alarm notification with LTE remote connection

This Didactum bundle combines the Monitoring System 500T with a Dry Contact expansion unit and an LTE modem to create a complete fault alarm system. This allows up to 32 potential-free contacts from existing systems at once — such as UPS systems, emergency generators, air conditioning systems, fire alarm systems, or collective fault contacts — to be centrally monitored around the clock via IP.

As a highly advanced 19"-1U control unit, the Monitoring System 500T forms the central alarm point of the bundle: it is integrated into the network via Gigabit Ethernet, is fully configurable via the web browser, and does not require additional software. The Dry Contact expansion unit is connected via the CAN bus and provides 32 additional inputs for potential-free contacts. The LTE modem already factory-installed in the expansion slot of the 500T ensures that alarm messages are reliably transmitted via mobile network even if the local network connection fails.

As your needs grow, this bundle grows with you: the Dry Contact expansion unit can be upgraded later with an additional board to 64 dry contacts, and the second CAN bus port on the 500T allows additional CAN devices and sensors to be added — without replacing the central unit.

This bundle includes:

Three perfectly coordinated Didactum products that together form a complete fault alarm system with mobile network backup.

Monitoring System 500T

The Monitoring System 500T is the central control unit of the bundle and a highly advanced, field-proven 19"-1U monitoring solution for data centers, server rooms, and other business-critical environments. As a self-contained device without moving parts such as fans or hard drives, it continuously detects all connected sensors and fault alarm contacts and triggers real-time alerts long before they cause costly downtime. With 8 analog ports, one CAN bus port, 16 potential-free inputs, and 4 relay outputs, the 500T can also be used as an I/O controller for doors, fans, generators, or UPS systems. The system is now equipped with Gigabit Ethernet (10/100/1000 Mbit/s) and can be seamlessly integrated into monitoring environments such as Zabbix, PRTG, or Nagios thanks to SNMP, Modbus TCP/IP, and Syslog.

Dry Contact expansion unit

The Dry Contact expansion unit was specially developed for Didactum high-end monitoring systems and enables IP-based monitoring of potential-free contacts from existing systems — such as collective fault contacts, UPS systems, air conditioning systems, or fire alarm systems. It is connected via the included 2 meter RJ12 cable to one of the two CAN bus ports of the Monitoring System 500T and is detected automatically. Each individual contact can be named separately in the web interface and assigned its own normal state (NO/NC) and its own alarm rules, so that, for example, if an air conditioning system fails, an SNMP trap can be sent automatically or a relay can be switched.

LTE modem with additional antenna

The LTE modem is already factory-installed in the intended expansion slot of the Monitoring System 500T and ensures maximum fail-safe operation of the fault alarm system. If the local network connection fails, the modem automatically switches to LTE (4G) and keeps the system communication running, so alarms from the Dry Contact expansion unit are reliably transmitted even when the LAN is unavailable. In addition, the module supports sending and receiving SMS notifications to up to ten different phone numbers, which significantly increases response speed for critical fault alerts.

Comprehensive contact and sensor integration for the bundle

The Monitoring System 500T supports up to 130 sensors, contacts, and relays simultaneously — 8 analog RJ12 sensor ports are available directly on the device, and this number can be significantly expanded via the CAN bus. The Dry Contact expansion unit included in the bundle additionally provides 32 inputs for potential-free contacts, while all 8 analog ports of the central unit remain fully available for classic sensor technology.

Thanks to the eight fully free analog ports and the second CAN bus port, the bundle can be expanded at any time with classic environmental sensors — the fault alarm system serves as the basis for comprehensive IT and building monitoring.

Real-time monitoring and automated alerting

The Monitoring System 500T reacts immediately to every state change of the connected fault alarm contacts. In the event of a fault, the system automatically sends email notifications, SMS, web-to-SMS, PUSH messages, or SNMP traps, or activates a siren. If the local network connection fails, the factory-installed LTE modem automatically takes over communication and ensures that alarms and SMS notifications continue to be delivered reliably. Integration into monitoring software such as Zabbix, PRTG, or Nagios is easily possible thanks to common network protocols (HTTP, HTTPS, SMTP, FTP, SNMP, Syslog, DHCP, Modbus TCP/IP).

Web-based control & intelligent automation

The intuitive web interface allows simple management of all fault alarm contacts as well as alarms and scenarios — directly from commissioning of the bundle.

• Fault alarm contact “UPS system” triggered → send SNMP trap, SMS to technicians
• Fault alarm contact “Emergency diesel generator” triggered → email to control room, switch relay
• Network outage detected → automatic switch to LTE, SMS confirmation
• Fault alarm contact “Air conditioning unit” triggered → activate backup air conditioning

The Monitoring System 500T can be used as an I/O controller for air conditioning systems, UPS, generators, lighting, doors, or fans — ideal for data center management, building automation, and preventive maintenance.

Full control

Monitor all fault alarm contacts, turn them into actionable alarms, and configure integrations — all via an intuitive, web-based interface.

• Monitor the real-time status of all 32 fault alarm contacts together
• Create automated actions based on defined conditions
• Send email, Telegram, HTTP request, SNMP, or other notifications
• Visualize trends and logs for better decisions
• Manage users, permissions, and access securely

Scalable, reliable, and future-proof

The Monitoring System 500T in the bundle is equipped with 10/100/1000 Mbit/s Ethernet (Gigabit). The system supports up to 1000 elements (sensors, contacts, triggers, timers, logic schemes, notifications). The Dry Contact expansion unit included in the bundle provides 32 contact inputs and can be upgraded with an additional board to 64 ports if required. All 8 analog ports of the central unit as well as the second CAN bus port remain fully available for additional sensors. Regular firmware updates ensure long-term use. Made in the EU — German support included.

Connect CAN devices

The Monitoring System 500T has two CAN bus ports. Up to 8 Dry Contact expansion units can be daisy-chained on each port, allowing the fault alarm system to be expanded with additional contact units or classic CAN sensors (temperature, humidity, smoke, water) as needed. The total length of a CAN bus chain can be up to 225 m, so even large infrastructures can be monitored centrally. An additional CAN power supply (12V/1A) is only required if the number of CAN devices in the chain exceeds 12 units.

Commissioning in just a few minutes

Setting up the bundle is simple and quick — completely without additional software.

1. Mount the Monitoring System 500T in the 19" rack and connect it to your network via Gigabit Ethernet cable
2. Connect the appropriate power supply — the system starts automatically
3. Open the device’s standard IP address specified in the quick guide in your browser and run through the setup wizard
4. Connect the Dry Contact expansion unit to one of the CAN bus ports using the included RJ12 cable — automatic detection
5. Connect the potential-free contacts of existing systems (e.g. UPS, air conditioning, emergency power) to the expansion unit using 2-wire signal cable
6. Insert your own SIM card into the already factory-installed LTE modem and activate it in the web interface
7. Name each contact in the web interface, define the normal state (NO/NC), and configure alarm rules

What is included in the package

Please check the scope of delivery for completeness upon receipt and report any missing or damaged parts to your supplier immediately.

• Didactum 500T monitoring unit1 piece
• OTG USB-C cable1 piece
• UTP Ethernet cable, 3 m1 piece
• Micro USB-C OTG adapter cable1 piece
• 19" rack brackets2 pieces
• M3 × 8 mm Phillips flat-head screws6 pieces
• Connection terminal, 6-pin, 5.08 mm1 piece
• Connection terminal, 3-pin, 3.81 mm1 piece
• Connection terminal, 6-pin, 3.5 mm4 pieces
• Connection plug, 2-pin, 3.81 mm15 pieces
• Self-adhesive rubber feet4 pieces
• Quick guide1 piece
• Dry Contact expansion unit (32 ports)1 piece
• RJ12 connection cable, 2 m1 piece
• LTE modem with additional antenna1 piece

A SIM card for the LTE modem is not included and must be purchased separately. The optional additional board for 64 dry contacts as well as a power supply variant can be selected if needed directly in the respective product option of the central unit.

Why this bundle is the right choice

Practical application examples

• Central collective alarming of UPS systems, emergency generators, and air conditioning systems
• Integration of heating, ventilation, and air conditioning (HVAC) systems into IT monitoring
• Connection of existing fire alarm and fault alarm systems to a central monitoring solution
• Remote monitoring of branch offices or remote sites without stable internet access thanks to LTE
• Backup communication for critical networks in data centers, hospitals, or public authorities
• Auditable event logging of all fault alerts for audits and compliance

This bundle of Monitoring System 500T, Dry Contact expansion unit, and LTE modem combines central IP collective alarming with fail-safe mobile network backup communication — for a reliable fault alarm system that continues to alert even when the network fails.

More about the bundle

Frequently asked questions