Installation of I / O Dry Contacts to Didactum`s remote monitoring devices

All IP-based remote monitoring units from manufacturer Didactum are equipped with inputs for Dry Contacts. A Dry Contact is also referred to as a potential-free contact or reed contact. A potential-free contact has two possible switching states: Normally Open (NO)) or Normally Closed (NC).

With the support of Dry Contacts / potential-free contacts, status and fault messages from machines and important HVAC systems are transmitted to the Ethernet-based remote monitoring devices of Didactum.

If the Dry Contact is switched, the IP-based monitoring device will send notifications and alarms via e-mail and / or SMS (via GRPS / GSM modem or e-mail to SMS gateway).
In addition, SNMP traps can be sent to building or network management solutions (such as Nagios, OpenNMS, or WhatsUp Gold). The IP networked remote monitoring unit from Didactum also support SNMPwalk functions. So the potential-free contacts / dry contacts can queried remotely at time intervals via TCP / IP network.

By means of the actuator function, the Didactum remote monitoring device can also automatically carry out measures such as the switching of 12V relay outputs. All events are recorded in the Syslog database of the Didactum monitoring device including time and date stamp.

Connection of Dry Contacts

Here we show you how to connect the AS-400 Dry Contact Management Card for UPS systems to the IP-based Monitoring System 500 II. With the support of the UPS management board, the IP-networked Monitoring System 500 II will receive following notifications:

  • UPS battery operation
  • Failure of the UPS
  • Collective alert (UPS runs on battery / charge state of UPS battery / internal UPS fault)
  • UPS is in bypass mode
  • UPS is running on battery mode
Dry Contact board for UPS
Fig.1: See the bottom of the UPS Dry Contact card. Below you see the description of the potential-free I / O contacts.

I/O connectors of Dry Contact Management Card
Fig.2: Below you see the I / O contacts of the UPS management card. Simply connect two-wire cables to the Dry Contact terminals. The exact pin assignment can be found in the manual of your Dry Contact I/O Management Card.

Connection of Dry Contacts to remote monitoring unit.
Fig.3: See here the Ethernet enabled 500 II remote monitoring device including the optional expansion board. The outputs of the UPS Dry Contact Management Card are connected to the potential-free inputs (DRY CONTACTS IN).

Configuration of Dry Contact Inputs
Fig.4: In the web interface of your Didactum remote monitoring device, you can individually configure each Dry Contact input. Define the name and define the normal state (Normal open / Normal closed) of each Dry Contact.

Create nofifications and alerts for connected dry contacts
Fig.5: In the built-in logic of Didactum`s IP-based remote monitoring unit, you can define notifications and alerts for each Dry Contact/ potential-free contact.

In addition, actuator functions, such as the automatic switching of relays or 12V outputs, are supported by the Ethernet-enabled 500 II remote monitoring unit.


CAN unit for Dry Contact connection
Fig.6: With the Dry Contact unit (item No. 14028) the 500 II monitoring device can additionally monitor up to 64 potential-free contacts via IP network. Use Didactum`s tried-and-tested 500 II remote monitoring device to connect existing power supply systems, emergency power units, sprinkler systems, air conditioning systems, video monitoring systems, CO2 extinguishing systems, alarm systems, etc.