Rugged instrumentation for reliable measurement and control

Applications By Industry

Search Applications

Redundant Trip Sources

There are many applications where the process alarm trip is critical. In these cases, if the process equipment is not brought to a safe condition it can cause expensive maintenance, production loss, or environmental impact. The commercial impact is enough that the cost of a second or redundant trip source is negligible.

Reasons for redundant alarm trips:

  • Loss of flow requires that a pump be shut down to protect it
  • If final pH correction is out of specification, you need to divert the effluent
  • High vibration on a large motor or pump mandates a shutdown
  • A high rate of change in reactor temperature requires a shutdown
  • High pressure at a spec break needs the source shutoff

Redundant Trips Sources
Download the PDF file

If a PLC or other BPCS is available, it commonly provides only one trip execution. Adding a stand-alone process trip to the loop provides a redundant trip source, preventing common mode failure. Moore Industries’ SPA2 model is a high volume choice for this trip.

When a BPCS is not available, stand-alone alarm trips such as the SPA2, can take on the task. Hard alarm trips complement a PLC by providing redundancy, simple control, and critical safeguarding. Hard alarms are not exposed to adverse effects of common-mode failure because they maintain complete independence from the PLC or DCS.

Key attributes:

  • Accept a signal input from transmitters, temperature sensors and a wide array of other monitoring and control instruments
  • Dual and quad alarm trip outputs
  • Site- and PC-programmable

Check out the SPA2 datasheet and Moore Industries Online catalog for more information.