Mitsubishi Electric FR-A800, Instruction Manual

Page: 819 / 1042

Parameters (N) Operation via communication and its settings
FR-A800 5 - 639
Read Holding Register access Log (H46 or 70)
●
Queries by function codes H03 and H10 are supported.
The number and start address of holding registers successfully accessed by the previous commu-
nication are returned.
"0" is returned for both the number and start address for queries other than the function codes.
●
Query message
●
Normal response (Response message)
●
Query message setting
●
Content of normal response
Slave Address Function CRC Check
(8 bits)
H46
(8 bits)
L
(8 bits)
H
(8 bits)
Slave Address Function Starting Address No. of Points CRC Check
(8 bits)
H46
(8 bits)
H
(8 bits)
L
(8 bits)
H
(8 bits)
L
(8 bits)
L
(8 bits)
H
(8 bits)
Message Description
Slave Address
Set the address to send messages to. Broadcast communication is not possible.
(Invalid when "0" is set.)
Function Set H46.
Tab. 5-288: Description of the query message
Message Description
Starting Address
The start address of the holding register that was successfully accessed is returned.
Start address = start register address (decimal) – 40001
For example, when start address 0001 is returned, the holding register address that was
successfully accessed is 40002.
No. of Points The number of holding registers that were successfully accessed is returned.
Tab. 5-289: Description of normal response
Example
쑴
Read the successful register start address and number of successful accesses from slave address 25
(H19).
Query message
Normal response (Response message)
Two successful reads of start address 41007 (Pr. 7) are returned.
쑶
Slave Address Function CRC Check
H19
(8 bits)
H46
(8 bits)
H8B
(8 bits)
HD2
(8 bits)
Slave Address Function Starting Address No. of Points CRC Check
H19
(8 bits)
H10
(8 bits)
H03
(8 bits)
HEE
(8 bits)
H00
(8 bits)
H02
(8 bits)
H22
(8 bits)
H61
(8 bits)