In a blog posted late last month I addressed how to provide a 24VDC source of power to a three wire field device. In the past I have used a 24VDC High Side Discrete output to provide 24VDC to these types of devices. This solution can be implemented in most DCS and PLC systems. If …
Tag Archive: “distributed control system”
Apr
28
Providing 24VDC to Field Devices
Some field devices such as an inductive proximity switch may be designed as three wire devices that require a 24VDC source of power. In such cases it is possible to tap into the 24 volt bulk power supply in the rack room and run twisted pair to the device. However, to protect against a short …
Jun
25
Distributed Control Systems’ Implementation of Mode
To ease operator transition from panel-based systems to monitor-based systems, the manner in which first generation Distributed Control Systems (DCS) displayed information often mimicked the way this information had earlier appeared on the control panel. Since the control interface provided by the control panel was familiar and had proven to be effective, a similar presentation …