4.5 Connection With a PLC 4.5.1 Automatic Communication Settings Function
After turning on the power supply, if there is not response from the PLC connected to the GT, the GT
switches to the automatic setting mode for the communication conditions. In the automatic setting mode,
commands are sent to the PLC while changing the communication conditions in the sequence shown
below.
The GT, in automatic setting mode, continues to repeat steps to until there is a response from the
PLC. While it is repeating there steps, it is in the “Standby” mode under “Configuration” →
“Communication Parameters” → “Handle Communication Error” on GTWIN.
Explanation of this function:
- Conditions when the automatic settings mode is in effect
If communication is attempted the specified number of times and there is no response from the PLC,
the GT goes into the automatic settings mode. The number of attempts is specified using the “No. of
Retries” parameter under “GT Configuration” → “Communication Parameters” → “Handle
Communication Error” on GTWIN.
- Automatically set communication conditions
In the automatic settings mode, if there is a response from the PLC, subsequent communication is
carried out under conditions matching the response. The main unit configuration settings are not
updated, however, even if the communication parameters are different from those of the main unit
configuration settings.
Note:
- An error response from the PLC is taken as a response, and the GT does not go into the automatic
settings mode.
- If the unit is connected to the COM port of the FP0/FP1/FP2/FP2SH/FP-M, communication between the
FP device and the PLC will not be possible if the target usage of the RS232C port has not been set to
“Computer Link”. Always set the setting on the PLC side to match “Computer Link”.
- The automatic communication settings function cannot be used for the communcation at 230400 bps
on the GT01, GT11 or GT21.
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