Host Communication

[Lim]

While a T100MD PLC is running, a host computer send ASCII string commands to it to read or write to its inputs, outputs, relays, timers, counters and all the internal variables. The serial port settings of T100MD PLC for host-link communication are : 38400 baud, 8 data bit, 1 stop bit, no parity.  If a host computer send ASCII string commands to T100MD PLC, it responds 'Warning: No Response from PLC'...
Why not? Answer me.....

[support]

Please describe your experience more clearly.

1) What software are you using to send the "ASCII" command?

2) Are you using TLServer to send the command? TLServer only accept the "multi-point" host link command (except "IR*" command, which is point-to-point) of the format "@nnHHxxxxff*". You will have to configure the command correctly and send to the PLC.

The T100MD PLC accepts a few different protocols:

a) Native hostlink command (as described above)
b) MODBUS RTU command
c) MODBUS ASCII command

You have to send command in the format acceptable by the PLC in order to get a response.

3) You have to check to ensure that the COM port is correct, the PLC is not currently writing out of COM port using PRINT, OUTCOMM or NETCMD$.  All these are factors that can affect the communication.

Are you able to perform online monitoring and program transfer using TRiLOGI software?

[eveningi]

 
1) What software are you using to send the "ASCII" command?  

---> I use Sample Programm(visual basic) downloaded from Frequently Asked Questions. And COM port is correct. While a T100MD PLC is not running, a host computer can read . While a T100MD PLC is  running, a host computer can't read using VBasic comms.
 
  Are you able to perform online monitoring and program transfer using TRiLOGI software?  

--->While a T100MD PLC is  running, I can't monitoring using TRiLOGI software  

I hope append ladder source I was made.
I think that ladder source aroused troubles in communication.
 

[support]

Is your program sending out data out of the COMM1 port? (i.e. execution of PRINT, OUTCOMM, NETCMD$, READMODBUS or WRITEMODBUS commands).  That will interfere with the PC trying to talk to the PLC.  Did you execute SETBAUD command has changed the COMM1 settings?

[Lim]

My program sending out data out of the COMM1 port.
ex)  @IR*chr(13) using VBasic comms
That will interfere with the PC trying to talk to the PLC.  I execute SETBAUD command(1th. COM1 9600bps, 8 data bits, 1 stop bit, no parity. 2th. COM1, 38400bps,  8 data bits, 1 stop bit, no parity)  changes the COMM1 settings.
See my ladder source.

[support]

I checked your program, you should change all the custom functions to differentiated format. i.e. use the {dCusF} and not the {CusFn}.

When you use {CusFn}, every time when it executes, it continuously write to the EEPROM using the SETTIMESV command. This is very bad for the EEPROM because you can overwrite it for more than 100,000 times very quickly and wear out the EEPROM.

Secondly, when the EEPROM is being written, the system interrupt is turned OFF to protect the integrity of the data. This explains why you have no communication because the PLC communication interrupt is also turned OFF and would not accept serial command.

When you use the {dCusF} command, the SETTIMERSV only executes once when the logic is true and this will not have any impact on the communication because the interrupt is only turned off briefly.

Regards,
support@tri-plc.com