Omron VARISPEED F7

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6
Slave Not Responding
In the following cases, the slave will ignore the write function.
• When a communications fault (overrun, framing, parity, or CRC-16) is detected in the command message.
• When the slave address in the command message and the slave address in the Inverter do not agree.
• When the gap between two blocks (8 bit) of a message exceeds 24 bits.
• When the command message data length is invalid.
Self-Diagnosis
The Inverter has a built-in function for self-diagnosing the serial communication interface circuits. This func-
tion is called the self-diagnosis function. It uses the connected communications parts of the send and receive
terminals to receive data sent by the Inverter and thereby to check if communication is performed normally.
To perform the self-diagnosis function use the following procedure.
1. Turn ON the inverter power supply, and set 67 (communications test mode) in parameter H1-05 (Terminal
S7 Function Selection).
2. Turn OFF the inverter power supply.
3. Perform the wiring according to Fig 6.78.
4. Turn ON the terminating resistance. (Turn ON pin 1 on DIP switch 1.)
5. Turn ON the inverter power supply.
Fig 6.78 Communication Terminals Wiring for Self-Diagnosis
During normal operation, the Digital Operator displays “PASS” on the display.
If a fault occurs, a “CE” (MEMOBUS communications fault) alarm will be displayed on the Digital Operator,
the fault output will be turned ON, and the Inverter operation ready signal will be turned OFF.
INFO
If the slave address specified in the command message is 0, all slaves execute the write function,
but do not return response messages to the master.
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