Add docs

SCHNDR/iocBoot/iocSCHNDR-IOC-01/README.md

@@ -1,3 +1,5 @@
 Put commands related to device addresses and Db files to load
 into a file in the `devices` sub-directory and then specify this
 file via the configuration macro `DEVCMD`
+
+See https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/Schneider-PLC

SCHNDR/iocBoot/iocSCHNDR-IOC-01/devices/GEMGateValve.cmd

@@ -5,13 +5,14 @@
 #  Read holding registers             3 
 #  Preset/write multiple registers   16 
 # length always specified in number of 16 bit words,
-# address here is 1 less than in chopper register doc with 40xxx prefix removed 
+# address here is 1 less PLC address plus 4xxxx prefix removed for code 3
 
 ## a readback of > 0 on a write (code 16) configure line below means it does a 
 ## single initial read of the value on IOC startup. code1
 ## 3rd arg is PLC slave address, check on PLC for this. Doesn't seem important for TCP,
 ## but is for RTU/ASCII
-## subtract 40001 from 40x register addresses that are read by code 3
+## subtract 40001 offset from 4x register addresses that are read by code 3
+## addresss here are 41315 and 40650
 drvModbusAsynConfigure("$(PLC)heartbeat", "$(PLC)", 1, 3, 649, 1, 0, 1000, "PLC")
 drvModbusAsynConfigure("$(PLC)gatevalve", "$(PLC)", 1, 3, 1314, 1, 0, 1000, "PLC")
 

SCHNDR/iocBoot/iocSCHNDR-IOC-01/devices/missing.cmd

@@ -1,3 +1,3 @@
 ##
-msgBox("ERROR: $(IOCNAME) - no device is defined")
+msgBox("ERROR: $(IOCNAME) - no device is defined", "See https://github.com/ISISComputingGroup/ibex_developers_manual/wiki/Schneider-PLC")
 ##