This option is used when the output of the temperature converter or pulse isolator module is thought to need re-calibrating. To perform this function a milli-ammeter with an accuracy of ±1μA or better needs to be connected to the output of the module.
The module compares the output current with the actual current seen on the meter. The module then calculates the adjustment needed to correct the error, and stores these values in non-volatile memory.
At first the module sets its output to 4.000 mA and the user then enters the reading from the meter. The module then sets the output to 20.000 mA and again the user enters the value seen on the meter. Once this procedure is complete the module calculates the adjustment needed.
The access to this feature is unlocked when the password is entered as it interrupts the functional dependency between input and output.
This should only be activated while the process variable is not monitored by a closed-loop control system.