• The translator for the signals from the controller responsible for the main air compressor of the plant were not working properly so the temperature results being sent to the control room and historian were faulty.
  • The control room did not realize that it was running completely blind with regard to the main air compressor of the plant as the temperature measurements were not reaching the control room.
  • The problem was identified because temperature remained completely stable, even when the compressor was working. If the compressor is working, the temp typically should rise; it is not logical for it to stay completely stable.

Measurement Tags Alerted

  • Power
  • Temperature

How SAM GUARD®Helped

  • Sent an alert indicating a correlation between power and temperature stagnation, which indicated a problem of temperature measurement.
  • It identified that the problem was in the conversion unit between the two controlling systems, which was not functioning properly.


  • The control room was running blind and could not see the actual situation with the compressor; if something had gone wrong, they would not have known; SAM GUARD® enabled them to see the real situation.
  • A negative event in the essential, main air compressor of the plant may have caused a major failure, especially if not caught quickly.
Air System Compressor Petrochemical-plant use case