Modular gas detection controller

Paul Boughton

The modular design of the new REGARD 3900 Gas Detection Controller means that the system can be extended or changed at any time to meet the future needs of the application.

Standalone and self-contained, the unit interfaces with transmitters to detect toxic, oxygen and explosive (Ex) hazards and, with its robust IP65 housing, can be installed in almost any location.

Depending on the type of input/output boards installed, the REGARD 3900 is fully configurable between 1 and 16 channels. Standard 4-20mA input boards can be mixed with relay output boards within the same REGARD 3900 control system. A combination of up to four boards can be installed.

Up to four analogue input boards can be used in a single REGARD 3900 and each board caters for up to four 2 or 3-wire 4 to 20mA transmitters, each of which connects to dedicated field terminals. Individual input boards are populated with three relays offering common fault, alarm 1 and alarm 2 SPCO outputs. To further enhance flexibility, each alarm level is also fully configurable and can be set as rising or falling, latching or non-latching.

The controller can be fitted with up to two relay output boards, each populated with eight additional SPCO relays. Relay 1 on each board is a dedicated fault relay and the remaining seven can be configured as single, common, voting, inhibit or non-operational.

An additional alarm 3 level and a second fault threshold are offered and each of the configurable relays can be set as rising/falling, latching/non-latching and energised normally or on alarm.

Configuration is quick and simple via a laptop PC using Config 3900 software to perform all calibration routines, zero and span. With new installations, the configuration can be performed offline and then uploaded during commissioning whereas, for service functions, the system configuration can be downloaded from the REGARD 3900 to the PC for verification.

For more information, visit