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Problem

How does one change cabling on the GBT?

Solution

Besides physically disconnecting and reconnecting cables carrying IF and LO analog signals or optical fibers, it is necessary to make the changes known to the GBT software. This may be done by first providing the IFManager with a connectivity file consisting of one line per cable which indicates the begin and end port, e.g.:

# LO Router Synthesizer Inputs
LO1A:J1 -> LO1Router:LO_1A
LO1B:J1 -> LO1Router:LO_1B
NC -> LO1Router:Aux_Ain
NC -> LO1Router:Aux_Bin

# LO1Router - TestTone/Phase Cal Outputs
# LO1Router:S13_J1 -> RcvrPF_1:Phase_Cal      # WC
LO1Router:S13_J1 -> RcvrPF_2:Phase_Cal          # WC
LO1Router:S13_J2 -> Rcvr1_2:Phase_Cal      # WC165
LO1Router:S13_J3 -> Rcvr4_6:Phase_Cal      # WC167
LO1Router:S13_J4 -> Rcvr12_18:Phase_Cal      # WC169
LO1Router:S13_J5 -> Rcvr2_3:Phase_Cal      # WC166
LO1Router:S13_J6 -> NC

To Temporarily Remove a Device from GBT Cabling:

Removing devices requires more than just commenting out pertinent lines in the cabling file, the software must also know the state of connections to and from the device or the IF Manager could crash. 'NC,' a/k/a 'No Connection' is used, but a format that makes reconnection straightforward by indicating how the normal connections are made should be used and is demonstrated in the following examples.

To disconnect at the beginning of a standard.cabling file line:

RcvrPF_1:XLA_IF -> PF_IF_Conditioner:J1

You edit to show:

# RcvrPF_1:XLA_IF
NC -> PF_IF_Conditioner:J1

Note the insertion of '#' at the beginning of the line to comment out the device being removed, the carriage return after the device being removed to move the disconnected yet remaining device to a new line and the insertion of 'NC' at the beginning of the new line.

To disconnect at the middle of a standard.cabling file line:

LO1Router:S13_J1 -> RcvrPF_1:Phase_Cal

You edit to show:

LO1Router:S13_J1 -> NC # RcvrPF_1:Phase_Cal

Note the insertion of 'NC #' in the middle of the line.

Once the cabling file (normally standard.cabling) has been modified, the cable connections are made known to the software by having the IFManager read the file. In CLEO's IFManager window, from the File menu select Load Cabling list ... and select the cabling file. In addition, the LO1 needs to pick up from the IFManager any changes affecting the routing of LO1 signals between it and the receivers. To do this turn the LO1 _Off and then On in CLEO's LO1 window, from the Managers menu. The LO1 will query the IFManager which will enable it to route the LO1 signal to the selected receiver. A new version of standard.cabling must also be saved in revision control, contact Galen Watts, x2134 or a member of the Software Division to do this.

To reiterate:

1. Change cabling
2. Edit cabling file to reflect new cabling using the suggested formatting
3. Have the IFManager read the cabling file
4. Turn the LO1 Off then On
5. Have new versions of standard.cabling saved in revision control.

-- MarkClark - 24 Jan 2005