[Dsg-hallc_controls] PLC mods

[Steve Lassiter]

Greetings, 

The following updates/mods/tests have been made to the software on the SHMS and HMS PLCs. 

HMS: 
Added code to turn on/off spectrometer vacuum gauge and to read the gauge and its status. The "redundant" functions bock were left as original found in the SHMS as they do report different functions, one is for the gauge having an over voltage, the other is for the I/O channel being overvoltage which could occur if the wires are disconnected from the gauge. Currently the upper limit values for these two blocks are the same value but they need not be. The SHMS is unchanged from the original code. 

Added blocks to open and read the HMS shutter. 

Mods made to the Q3 program: 
Sheet 6 added functions 
Sheet 10 added for vacuum reading 
Q3_Carbon_glass: added rungs at bottom for Shutter control and readback 

Shutter readback on HMS. Here the quads have an unused module IB16D. Different from using an IF16 module as in the SHMS. Also the shutter is never removed from the detector hut as is with the SHMS. Thus far not tested but will need safety features just like the SHMS (see below). 

SHMS: (trying to do a s much as possible with the fewest number of I/O channels) 
Tested Shutter operation and readback tested. Found a safety issue. 
The PLC can open the SHMS shutter at any time when the command is sent. There is no hardware or code to prevent the shutter from opening if the barn door is open and personal are around the shutter. I was expecting hardware to prevent this from happening. Will add a tag that will only allow the command to go out if the hall is in beam permit mode ( after a sweep is has been done). Hardware will be modifyied to prevent shutter from opening (either via remote or local) if the barn door is opened. (This is not completely safe either example - HMS door is installed and closed, securing all interlocks, but part of the wall is removed, allowing shutter operation to occur with personal in vicinity of the vacuum window) 
Also determined that an unplugged shutter voltage signal does not generate a fault on the IF16 module. Cannot be used to determine if shutter is installed or not. A solution is to hardware a voltage divider into the existing signal to produce 10V when shutter is open, 5V when shutter is closed and 0V when shutter is removed. Will ask Joe B to handle this the hardware aspect. 

Steven 


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