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Technical support / Nano-10 +r74 ModbusRTU
« on: October 21, 2011, 05:56:40 PM »
One night, READMODBUS works great, but lots of unrelated ethernet communication faults from laptop to Nano. Next morning upgraded JRE and i-TRiLOGI to V6.43 as recommended to work around some Java issues. Laptop to Nano via ethernet works great! Thanks!
Next download, not one sucessful READMODBUS since. Only one other node on RS-485 network, node 2 temp/humidity sensor, still works correctly as tested using Modbus Poll software. Tried replacing Nano RS-485 transciever chip (TI75HVD3082 from Digikey), no joy. Have 1 x 83ohm terminator; no biasing resistors. Entire network is ~ 3' long on my desk. Maybe I overloaded the transciever chip terminating with 83ohm instead of 120ohm. Extremely suspicious that modbus failure was concurrent with upgrade to v6.43.
I always get a fault from the WRITEMODBUS code shown below:
CusFn 1 "Initialize":
SETLCD 0,1, CHR$(1)
SETLCD 1,1, "PLC Restarted"
'Sets baud for channel 1, 19.2k, 8 data bits, 1 stop bit, even parity
SETBAUD 1, &H44
'SETSYSTEM 6, 3 'ModbusRTU
'Sets the protocol for channel 1, Modbus RTU = 1 (or 0 - Auto sensing)
SETPROTOCOL 1, 1
' Set HUM2 to display Degrees F
' ModbusRTU, Node 2, Register 121, Value = 1
WRITEMODBUS 11, 2, 121, 1
IF status(2) THEN
SETLCD 2,1,"Node 2 Set to "+CHR$(223)+"F"
ELSE
SETLCD 2,1,"NODE 2 Write Failed"
ENDIF
Thanks for any help.
GN
Next download, not one sucessful READMODBUS since. Only one other node on RS-485 network, node 2 temp/humidity sensor, still works correctly as tested using Modbus Poll software. Tried replacing Nano RS-485 transciever chip (TI75HVD3082 from Digikey), no joy. Have 1 x 83ohm terminator; no biasing resistors. Entire network is ~ 3' long on my desk. Maybe I overloaded the transciever chip terminating with 83ohm instead of 120ohm. Extremely suspicious that modbus failure was concurrent with upgrade to v6.43.
I always get a fault from the WRITEMODBUS code shown below:
CusFn 1 "Initialize":
SETLCD 0,1, CHR$(1)
SETLCD 1,1, "PLC Restarted"
'Sets baud for channel 1, 19.2k, 8 data bits, 1 stop bit, even parity
SETBAUD 1, &H44
'SETSYSTEM 6, 3 'ModbusRTU
'Sets the protocol for channel 1, Modbus RTU = 1 (or 0 - Auto sensing)
SETPROTOCOL 1, 1
' Set HUM2 to display Degrees F
' ModbusRTU, Node 2, Register 121, Value = 1
WRITEMODBUS 11, 2, 121, 1
IF status(2) THEN
SETLCD 2,1,"Node 2 Set to "+CHR$(223)+"F"
ELSE
SETLCD 2,1,"NODE 2 Write Failed"
ENDIF
Thanks for any help.
GN