Azbil F4Q, User Manual

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8-1
Chapter 8. Troubleshooting
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Communication failure
• Check if the device is turned on. RS-485 communication is not possible during
fallback operation with USB power.
• Check the wiring.
• Check that the communication settings for this device are the same as those for
the host device.
If even one of the following settings differs, communication is not possible.
The underlined settings can be configured directly on the F4Q.
•
Transmission speed: 38400, 19200, 9600, 4800 bps
•
Data length: 7 bits, 8 bits
•
Stop bits: 1, 2
•
Parity: No parity, even, odd
• Check the communication protocol settings.
With this unit, the user can select either CPL communication or Modbus
communication (RTU mode). CPL communication is the default protocol.
Also, if the communication protocol setting is changed, this device needs to be
restarted in order to apply the new setting.
• Check that the device address in the command frame transmitted from the host
device matches the address set for the F4Q. “0” (no communication) is the the
default address of the F4Q, but if the device address in the command frame is set
to 00, the F4Q will not respond.
• Check that different device addresses are given to multi-dropped devices.
• Check that the communications timing conforms to 4 - 5 Timing Specifications
(p. 4-17)
.
• Check the command frame. Use capital letters in all character codes.