My Plus controller/indicator has a invalid Unlock code, why is this?

Submitted byglx25v onFri, 08/17/2018 - 17:29

This problem is almost certainly caused by electrical "noise", but it may enter the controller or indicator by a number of routes.
It could be line conducted via the mains supply or picked up and transmitted via signal input or even an SSR output if one is used. The other method could be airborne radiated noise from nearby equipment such as contactors, spark ignitors motors etc.

West controllers and indicators meet the latest CE European Directives regarding EMI susceptibility and EMI emissions (EN61326).
If the noise/spikes exceed the levels specified in these Directives, it is possible that the data held in the nonvolatile RAM is being corrupted, causing the controller to return to default values.

Relay output control outputs that are connected to an inductive load such as a contactor coil can be a source for this problem. ISE can supply a snubber to help correct. The snubber has an added benefit of increasing the controls internal relay life.

The cause of the noise must be identified and suppressed at source. Also, ensure that normal good practice is observed when installing and wiring the controllers. Do not run signal cables near to electrically noisy equipment, use a separate conduit for signal and power cables, use shielded cables (earthed at one point only).


The unlock codes must be changed to numbers that are acceptable (0-9999, default is 10 for Setup Mode and 20 for Configuration Mode) using the Configuration software.  The software can be purchased from ISE, P/N PS1-CON.  If controller problem is not resolved using software the unit must be sent in for repair.