Didactum Expansion Unit 32xDI (CAN)

Up to 64 potential-free contacts per CAN bus expansion

The Didactum Dry Contact Expansion Unit is a CAN bus expansion module specially developed for Didactum high-end monitoring systems. It was designed to make existing systems with alarm and switching contacts IP-based monitorable as part of the convergence of building technology and IT. Each unit provides 32 additional inputs for potential-free contacts in the standard version, connected via a 2-wire signal cable and monitored around the clock over the network or the internet.

The unit is connected via the included RJ12 patch cable to one of the two CAN bus ports of a Didactum Monitoring System (for example, 50T, 100T, 300T, 500T or 550T) and is automatically detected. In the integrated web server of the monitoring system, each individual contact can be named separately, assigned its own normal state (NO/NC), and linked to custom alarm rules or actions - for example, sending an SNMP trap or an SMS notification in the event of a fault.

Customers who require a higher total number of contacts can expand the unit with the optional "Dry Contacts Board" to a total of 64 potential-free contacts. Up to 8 units can also be chained per CAN bus branch, making it possible to centrally monitor even very large infrastructures with extensive alarm technology in an IP-based way.

Typical applications for the Dry Contact Expansion Unit

Wherever existing systems already have potential-free alarm or switching contacts, the expansion unit is an ideal solution.

What makes the Dry Contact Expansion Unit stand out

A simple, cascade-capable CAN bus expansion for IP-based monitoring of large numbers of potential-free contacts.

Individually configurable: number of dry contacts

The Dry Contact Expansion Unit can be tailored precisely to your requirements during the ordering process.

Number of dry contacts

Scalability in detail

Up to 8 Dry Contact Expansion Units can be chained per CAN bus branch of a Didactum Monitoring System. In combination with the 64-contact version, this results in up to 512 potential-free contacts on a single CAN bus branch - ideal for data centers, building complexes, or industrial plants with extensive alarm technology. Since Didactum Monitoring Systems typically have two CAN bus ports, this number can be doubled if needed.

An additional CAN power supply (CAN-12V-1A) is recommended as soon as several units are operated in a long chain, to ensure reliable power supply for all devices on the CAN bus.

Power supply and stability

The Dry Contact Expansion Unit requires only 1 watt of power and is supplied directly via the CAN bus by the connected Didactum Monitoring System - a separate power supply is usually not necessary. For larger installations with several daisy-chained units or long CAN bus chains, the additional CAN-12V-1A power supply is recommended; it is integrated directly into the CAN bus line and reliably powers all downstream devices. Without this additional power supply, voltage may drop too much in long chains or with many connected units, which can lead to unstable operation.

Flexible mounting options

The expansion unit can be mounted in three different ways depending on the installation site.

Setup in just a few steps

Commissioning is performed without additional software directly through the monitoring system's web front end.

1. Connect the Dry Contact Expansion Unit to one of the two CAN bus ports of the monitoring system using the included RJ12 patch cable (2 m).
2. Set the TR termination switch: "ON" for the last unit in the chain; for chains longer than 10 m, set it to "OFF"; leave the "FR" DIP switch permanently set to "OFF".
3. For multiple units or long chains, optionally integrate the CAN-12V-1A power supply into the CAN bus line.
4. Connect the potential-free contacts of the monitored systems to terminal points 1-32 (or 33-64 with board) using a 2-wire signal cable.
5. In the web interface of the Didactum Monitoring System, access the expansion unit and the automatically detected contacts.
6. Assign each contact individually, define the normal state (NO/NC), and configure the desired alarms or actions.

What is included in the box

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

• Dry Contact Expansion Unit1 piece
• RJ12 patch cable, 2 m1 piece
• Quick start guide1 piece

Optional available: the "Dry Contacts Board" for expansion to 64 contacts (factory installation available on request, or directly selectable via the "Includes 64 dry contacts" option when ordering), as well as the "CAN-12V-1A" power supply for additional power in longer CAN bus chains. Neither is automatically included in the scope of delivery.

Why the Dry Contact Expansion Unit is the right choice

Practical application examples

• TCP/IP integration of existing systems and plants with alarm or switching contacts
• IP integration of heating, ventilation, and air conditioning (HVAC) systems
• Integration of emergency power and fire alarm technology into network monitoring
• Integration of building technology into SNMP-compatible management software
• UPS monitoring by coupling emergency power and battery systems
• Access and door monitoring for server cabinets and technical rooms
• Monitoring pumps, fans, and other building technology
• Scaling large infrastructures with extensive alarm technology

The Didactum Dry Contact Expansion Unit enhances the capabilities of any Didactum Monitoring System by enabling the connection of large numbers of potential-free contacts, thereby ensuring comprehensive alarm monitoring and reliable protection of critical infrastructure.

More about the Dry Contact Expansion Unit

Frequently asked questions