The ALS shutters are controlled by two momentary EPICS channels, one to OPEN and one to CLOSE the shutter. Occassionally a guardian request to open/close one of these shutters is unsuccessful.

The requirement:

The status of the shutters to be added to SDF to show as a diff if they are not in their nominal state (CLOSED).

The problem:

Because the control channels are momentaries, even though these are automatically in the SDF they do not show actually the status of the shutters. Momentary records change state only for a fraction of a second and then return to their stand-by value of zero. The record which shows the shutter state is a monitor channel, and therefore not in the SDF.

I had two coding options:

1. change the existing slow controls systems for h1sysecat[x,y]1plc1sdf to make the monitor channels pseudo set-point channels and therefore in the SDF

2. create a whole new slow controls sdf just for ALS shutters

We decided on option 1.

Details:

I changed my code which generates the slow controls SDF monitor files to add the four shutter state channels for PLC1 at EX and EY. After restarting h1sysecat[x,y]1plc1sdf I ACCEPT+MON'ed the new channels.

The SDF system shows channel names, and unfortunately there is a naming issue with the EY system whereby the Green-beam and the Fiber-beam channels are reversed compared with EX. This is compounded by the fact that the names of the systems assume the channel swap has not happened, and are therefore wrong. To help operators which this possible source of confusion, I have modified the SYS_CUST_SHUTTER_SUMMARY MEDM to show any SDF differences as RED blocks. I have also removed the Green/Fiber naming confusion by hardcoding the EY names (they are colored BLUE to show I have done this).

New and Old MEDM images attached.