Hitachi EH-150 Series - Page 151

Chapter 7 System setup
7 - 7
 Check flow of Modbus slave mode
Reference :
 In case of the Modbus RTU, H80-HFF are contained in data. If 7-bit transmission format configuration is used,
CRC error will be detected, and a response will not return from slave device. Be sure to use 8-bit transmission
format configuration.
 Master might fail to receive data from slaves if response time is too short. Response time of EH-SIO is adjustable.
Please change this parameter if necessary.
Query transmission
Response
transmitted?
Replace the module.
YES
NO
Transmission speed
OK?
YES
YES
YES
Status of host
normal?
Contents of query
OK?
YES
NO
OK
Please set up a communication
setting switch again.
NO
Please set up a communication
setting switch again.
NO
Please connect a communication
cable correctly.
NO
Please change the host to a normal
state.
NO
Exception
response?
YES
NO
Please reconfirm the format of
query.
Please improve the designated
address by query.
Device No.
agreement?
YES
NO
Please improve the device No. of
query or the device No. of EH-SIO.
Broadcast
transmission?
NO
YES
OK
Transmission format
configuration OK?
Connection of
communication cable
OK?