Dry Contact Monitoring with SNMP

Modern IT departments rely on SNMP-based network management solutions for the holistic monitoring of the IT infrastructure. With the support of the SNMP versions V1, V2c and V3 (Simple Network Management Protocol), important status messages and measured values from various systems and devices are transmitted via the TCP / IP network.

So nowadays it is no problem to query remotely the current toner and counter status of printers and copiers installed in branches via SNMP. If an HDD in the NAS fails, a message is sent to the in the form of SNMP traps to Network-Monitoring-Systems (Nagios, Check MK, OpenNMS, PRTG, WhatsUp Gold, Zabbix). The admin can then act immediately. 

Problem case floating contacts / dry contacts

Many systems and systems in house and building technology, think of heating, ventilation, refrigeration or air conditioning (HVAC), fire alarm systems and / or emergency power systems, are often not equipped with a network or an SNMP management card. Important maintenance, malfunction and error messages are signaled by these systems in a conventional manner via floating contacts / dry contacts. Here the facility manager and the IT manager are faced with the task of making these dry contacts "IP-capable". 

Ethernet connection of the house and building technology

The seamless integration of systems equipped with fault indicators / dry contacts contacts is easier than you think. Every smart monitoring system from manufacturer Didactum offers inputs for digital / dry contacts. The systems and machines equipped with these floating relay contacts are easily connected to these inputs.

This is done with the support of a simple two-wire cable, which connects the floating relay of the system to be monitored with the dry contact input of the SNMP-compatible Didactum remote monitoring & control unit. Connected dry contacts are configured individually in the English-language web interface of the Didactum Monitoring System. Here the user defines the normal state of the connected dry contacts (NO = normally open or NC = normally closed).

The dry contact of the air conditioning system or the emergency power generator can even be named individually, if required. This gives the user detailed information about which machine or system is reporting a malfunction. The current switching status of the dry contact is also shown graphically in the web interface of the remote monitor. 

Warning and alarm functions

If, for example, a malfunction occurs with the air conditioning or the heat pump, this is immediately detected by the SNMP-capable monitoring unit. Messages and alarms are sent to the responsible technicians and facility managers in the form of email and SMS notifications. The external service provider, such as the responsible refrigeration and air conditioning company, can even be informed of the current fault using the dial function (GSM / 4G-LTE modem required).

All events and status changes are saved in the syslog database of the networked remote monitoring unit. Upon request, this can be sent regularly to the company headquarters, where the syslog is then evaluated. 

SNMP traps when dry contacts are triggered

The smart measuring and control devices from Didactum are fully SNMP compatible. The messages from the connected floating (dry) contacts can also be sent in the form of so-called "SNMP traps" to automation, building or network management software. This means that the current operating status of the heating or air conditioning can also be reliably monitored remotely from the control center. Upon request, each individual dry contact fault indicator can be queried by the management software using an SNMP walk command.

The integrated 12 volt outputs of the networked remote monitoring system can even control pumps and switch alarm sirens. The extensive logic functions support the mapping of individual escalation and alarm plans. 

Monitor single or multiple dry contacts in real time

Didactum offers SNMP compatible fault reporting systems for every size. Even with the entry-level model in the form of the Monitoring System 50, up to 2 fault indicators can be remotely monitored via SNMP. In addition, important critical warnings and important information are transmitted via email and SMS. The content of the notification can be defined individually.

The high-end systems of the model series 600 and 700 can monitor hundreds of floating (dry) contacts around the clock in real time and reliably notify employees.

Integration in management solutions

Each Didactum monitoring device works independently, so there is no need to install software or additional hardware. Installation and operation is very easy via the multilingual web interface. The MIB file required for integration into SNMP-compatible management solutions is simply downloaded from the web interface and imported into the management software. Didactum provides plugins for Nagios and Nagios forks 2 as well as templates for Zabbix.