Hitachi EH-150 Series Applications Manual page 108

Chapter 6 Communication Mode
 Function code 0x03 (Read Holding Registers)
For EH-SIO, this function code means "Read status of internal output (WR)". Broadcasting is not supported.
(1) Query
The start address of the internal output (WR) and the number of internal outputs to be read are specified in the
query.
« Note »
A start address should specify I/O number of WR. (For WRF000, the address is specified as HF000.)
(2) Response
Response is sent back automatically according to query. Response is returned in an order from the high byte of the
specified address.
« Note »
If requested address or a part of data is not assigned as WR range, exception response will be returned.
(3) Example
Read the status of WR9A02-WR9A03 (2 words) in the slave 10.
WR9A02
H 4 9 2 A
WR9A03
H C 1 F 5
Query
Field name
Slave address
Function code
Holding register head address (upper)
Holding register head address (lower)
Holding registers number (upper)
Holding registers number (lower)
Error check
Data of WR9A02-WR9A03 is stored in an order from the high byte.
Response
Example Field name
(HEX)
0 A Slave address
0 3 Function code
9 A Number of data bytes
0 2 Holding register data 1 (upper)
0 0 Holding register data 1 (lower)
0 2 Holding register data 2 (upper)
[CRC] Holding register data 2 (lower)
Error check
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Example
(HEX)
0 A
0 3
0 4
4 9
2 A
C 1
F 5
[CRC]