Today with help from Daniel Sigg and Patrick Thomas I changed the names of SQZ WFSA and SQZ WFSB to H1:ASC-AS_A/B_RF42 , so that they will be consistent with the rest of our AS sensors and also to make clear that these are the same diodes as AS_A and AS_B.  This is easier to do now that it will be later, and this will allow us to make the names consistent between beckhoff and the RCG.  Because of the way the error handling is done in beckhoff, the easiest way to make this name change was to move the demods and whitening for these WFS from PLC4 to PLC2.  The whitening for these WFS as well as squeezer LSC whitening was already read into PLC2 then sent to PLC4 

Details for the record (this is a little pedantic so that it might be useful for people trying to remember how to make changes in beckhoff):

To make the changes in PLC2:

• Under Data types tab:  add Rf43 to WfsAsAStruct and WfsASBStruct
• Under Resources tab: add RF42 to Global_WfsAsAStruct_Errors and Global_WfsAsBStruct_Errors. Do nothing under Global_Variables_ISC where the whitening for these WFS is read in and out as IscWhitening5 so that the channels that need to be shipped to PLC4 for the SQZ LSC are still sent. Add structures under Global_Variables_ASC to read in the demods (assigning them addresses that leave enough spaces between assigned addresses), and the whitening. 
• Under POU tab: in ASC POU add function blocks for both WFS RF42 Demods, Whitening (using correct variables for whitening), and Error Handlers, also declare a variable for RF42 error handling for both WFS.  In the ISC POU only copy ISC Whitening chassis 3 (instead of 1,2 and 3) into and out of the structure that gets sent to PLC4. 

Changes in PLC4 were easier, just delete everything that has to do with the SQZWFS in all three tabs. 

Reminder: After making changes in the target area, if you save in the svn area you need to fix the links that would be broken for LLO if you were to comitt.  You can do this by going to the Resources tab, and right clicking on Global_Variables_Version, choosing Object Properties and make sure the path is C:SlowControlsTwinCATSourceCurrentInterferometerVersion.exp; do the same for Global_Variables_IfoVar to C:SlowControlsTwinCATSourceCurrentInterferometerCornerIfoVar.exp

After making the PLC changes, rebuilding and logging in and running both PLCs, I opened the LHO system manager and under the PLC tab right click on the PLCs you changed and choose Rescan Project....  For the whitening no changes were necessary, but for the demods you have to link the new variables to the correct channels of the correct modules. (Wiring diagrams for beckhoff chassis can be found under this document tree: https://dcc.ligo.org/LIGO-E1200204)  The easiest way to do the linking might be to find the hardware under the Cofiguration tab (most corner stuff is under I/O Devices/ Device 1(EtherCAT) /Corner MSR L0 (EK1101)/ Corner MSR L8_9 Vertex, when you locate the module you need right click on it to choose the variable you want to link it to. After making changes to the system manager under Actions you can in order select Generate Mappings, then Check Configuration, then Activate Configuration, then Set/Rest TwinCAT to Run Mode 

If things are fine, you can copy the .tsm file from the target area to the svn directory (C:SlowControlsScriptsConfigurationH1ECATC1SYS or similar).  To make the changes to the system manager for LLO, I first committed everything I had done so far to the SVN, then updated from the SVN, then opened the install scripts (icon looks like a bunch of gears) choose the appropriate LLO target and ran Update from Source and Compile.  Then we had a target area for LLO, where I went to open the LLO system manager, scan the PLCs, make the links, then save this into the svn directory. 

Finally, there were 4 documents that were updated to reflect this change:

• Whitening List 
• ADC and DAC channel list 
• Corner Chassis 4 Wiring diagram 
• EtherCAT Corner Channel link list