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6674 PSU Over Current Protection Delay

Question asked by ihfc on Apr 1, 2014
Latest reply on Apr 22, 2014 by MattC

I'm having trouble getting a 6674A PSU to signal an OCP fault in less than 20 seconds when monitoring faults via the Questionable Status register. I've enabled over-current protection, and set the right bits to have a protection condition trip the PSU on an Over-Current fault, but the PSU will wait 20 seconds before it bothers to set the OCP bit in the Questionable Status register. I had assumed this was down to the OUTPUT:PROTECTION:DELAY being set to a default value of 20, but after changing it to a lesser value (0, 1, 2, etc.) and confirming that it was set to the new value, the PSU still waits 20 seconds before setting the Questionable status accordingly. The indication of the OCP is indicated instantly in the CURR:PROT:STAT? value, but I'd set my software to read all Protection faults via the STAT:QUES:EVEN? query, and would rather not bodge in a fix for one of the flags....

Is there something else that needs to be done to make the PSU use the new value, or am I setting the wrong values all together?