Issues with the alarm points and hysteresis settings of secondary instruments?
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Hello, colleagues in the instrumentation field. I would like to ask for your advice: For example, in an intelligent digital display controller (commonly known as a secondary control instrument), there are low alarm (LA), high alarm (HA), low-low alarm (LLA), and high-high alarm (HHA). How should these settings be determined based on the actual alarm values and setpoint tolerance parameters at the site? For example: Suppose this instrument is used to determine whether the condensate is contaminated based on its conductivity value – a conductivity range of 400–500 indicates acceptable condensate, while a conductivity range of 520–600 indicates unacceptable condensate. Using these values to control the three-way valve, how should the alarm threshold values be set in the instrument? Thank you.
The setting of alarm values is the responsibility of the process engineering team, while the differential instruments are determined by the relevant engineering team; communication between these teams is necessary in practical applications
OP on the second floor, could you provide a more detailed answer?
This should be handled by the process engineering team, which can provide instrument designers; the alarm parameters can also be adjusted after the instruments have been installed
Set the low value to 400 according to STE, and the high value to 520
Alarms are set in accordance with safety and process requirements; they cannot be adjusted arbitrarily by instrument technicians.
These instruments should all be standard or pre-set, right?