Hitachi EH-150 Series - Page 115

Chapter 6 Communication Mode
6 - 73
Modbus Slave
 While modbus slave operation
Error code is indicated in high byte of status area WXus2, 3. (If error level is warning, EH-SIO keeps working.) If
the next query is processed properly, error code in WXus2, 3 is cleared. If TRNS 9 command is issued while
modbus slave mode, “Invalid command error (H50)” is given in the return code area of TRNS 9 command.
Table 6.18 Abnormalities during modbus slave mode operation
No.
Error
code
Item
Error
level
Details
1
HFF
CPU error
---
Operation of EH-SIO stops due to serious error of CPU module.
2
---
Watchdog timer error
Serious
error
MPU in EH-SIO does not work due to watchdog timer error.
3
H03
OS system error
Serious
error
Error is detected in system OS of EH-SIO.
4
H8A
Parity error
Warning
EH-SIO detected a parity error in query (
received message
).
5
H8B
Framing error
Warning
EH-SIO detected a framing error in query (
received message
).
6
H8C
Overrun error
Warning
EH-SIO detected an overrun error in query (
received message
).
7
H8D
Check code error
Warning
EH-SIO detected a validity abnormality in the check code of query
(
received message
).
8
H8E
Receiving timeout error
Warning
Data receiving was not completed with in specified time.
9
H8F
Transmitting
timeout error
Warning
Response sending was not completed with in specified time.
10
H91
Query error
Warning
Query (received message) has wrong data
« Note »
Error is checked in every byte. Different from modbus master mode or free protocol mode, only the latest error is
indicated in modbus slave mode. So if parity error or framing error is detected, it can be cleared check code error.
Please check the transmission format configuration and the transmission speed also in case of check code error.