The sensor expansion unit is one of Didactum's CAN-based units. CAN stands for Controller Area Network and is a serial fieldbus protocol that has proven itself for decades. The IT monitoring systems of the 100/300/500/500-DC/500 II/500 II DC series are equipped with a CAN port. Digital CAN sensors and CAN units can be connected here via plug and play.

This CAN unit was developed to increase the number of connections required for intelligent sensors. For example, by installing the CAN unit on the 100 III monitoring system, the number of connections for intelligent sensors can be increased from 4 to 12 ports. If additional sensor connections are needed later, simply connect another sensor expansion unit.

The monitoring system acquires measurement data from the connected sensors in real time.

The "Error" LED indicates a faulty connection.

The CAN expansion unit can output the following signals:

• If the "Error" LED is constantly lit and the "RUN" LED is flashing, the CAN unit has no connection to the Didactum monitoring system.
• If the "Error" LED is constantly lit and the "RUN" LED is not lit, the CAN unit is connected to the Didactum main unit but has not yet been configured.
• If the "Error" LED is constantly off and the "RUN" LED is constantly lit, the CAN unit connected to the monitoring system is working correctly.

Connect the CAN 1 port of the expansion unit to the included RJ12 patch cable. Plug the other end of the patch cable into a CAN port on the previous CAN bus device or into the CAN bus port of your Didactum monitoring system.

The total length of the CAN bus for the 100 III / 500 II monitoring system must not exceed 205 meters! A CAN bus may consist of a maximum of 8 CAN sensors and/or CAN units.

Please adjust the Terminator (TR) DIP switch. If the CAN unit is located at the end of the CAN bus cabling, the Terminator must be set to "ON". Use the tip of a ballpoint pen to move the DIP switch of the CAN sensor expansion unit to the lower position while it is off. If CAN units or CAN sensors are located between the main unit and the last CAN device, they must not be terminated.

If only the CAN sensor expansion unit is connected to the CAN bus, the external power supply is not strictly necessary. However, if the RJ12 patch cable is longer than 10 meters and multiple CAN sensors and/or CAN units are connected to the CAN bus cable, the power supply should be connected.

Log in to the monitoring system using a web browser (Chrome/Firefox). Go to the "CAN Configuration" menu item. Then click on the "Config" selection field and confirm the CAN bus configuration. The scan will then start immediately.

Please note:

Depending on the total number of connected CAN sensors and/or CAN units, the scan may take several seconds. After the scan is complete, the detected CAN units and CAN sensors will be listed in a table. The CAN expansion unit for sensors detected by the monitoring system and the analog sensors connected to it can then be individually configured in the web interface under "System Tree." Under "Logical Scheme," define notifications and alarms in the form of actuator functions, SNMP traps, email, or SMS (via GSM modem).

Note:

If no CAN devices are detected by the monitoring system after the scan, please check the wiring of the CAN bus line and the terminator setting (TR) of the respective CAN devices. As previously mentioned, the CAN unit at the end of the CAN bus cabling must be terminated using a Terminator (TR) DIP switch! CAN sensors and/or CAN units located between the IT monitoring system and the last CAN device must not be terminated. Please check the status of the jumpers or DIP switches in these cases.

(Copyright Didactum. Version 07/2017. Technical specifications are subject to change without notice.)