Read Holding Register Access Log (H46 Or 70) - Mitsubishi Electric A800-E Instruction Manual

(N) Operation via communication and its settings
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 communication are returned.
"0" is returned for both the number and start address for queries other than the function codes above.
• Query message
a. Transaction b. Protocol
identifier identifier
H L H
(8 bits) (8 bits) (8 bits)
• Normal response (Response message)
a. Transaction b. Protocol
identifier identifier
H L H
(8 bits) (8 bits) (8 bits)
• Query message setting
Message
a Transaction identifier
b Protocol identifier
c Length field
d Unit identifier
e Function
• Content of normal response
Message
f Starting address
g No. of points
Example) Read the successful register start address and number of successful accesses from slave address 25 (H19).
Query message
Transaction Protocol
identifier identifier
H00
 
(8 bits)

A given value is set.
Normal response (Response message)
Transaction Protocol
identifier identifier
H00
 
(8 bits)

The values are the same as those in the query message.
Two successful reads of start address 41007 (Pr.7) are returned.
46
PARAMETER
c. Length
field
L H L
(8 bits)
(8 bits) (8 bits) (8 bits)
c. Length
field
L H L
(8 bits)
(8 bits) (8 bits) (8 bits)
The master adds the data for the purpose of transaction control.
The same data is returned in the response from the slave.
Fixed to 0. (When the slave receives data other than 0, it does not send the response
message.)
0 is returned in the response from the slave.
The data length from the unit identifier to the data is stored in byte.
Fixed to 255
Set H46.
The start address of the holding register that was successfully accessed is returned.
Starting address = start register address (decimal) - 40001
For example, when start address 0001 is returned, the holding register address that was
successfully accessed is 40002.
The number of holding registers that were successfully accessed is returned.
Length field
H00 H00 H02 H19
(8 bits) (8 bits) (8 bits) (8 bits)
Length field
H00 H00 H06 H19
(8 bits) (8 bits) (8 bits) (8 bits)
d. Unit
e. Function
identifier
H46
(8 bits)
d. Unit
e. Function
identifier
H46
(8 bits)
Unit
Function
identifier
H46
(8 bits)
Unit
Function
identifier
H10
(8 bits)
f. Starting g. No. of
address points
H L H
(8 bits) (8 bits) (8 bits)
Description
Description
Starting
No. of points
address
H03 HEE H00
(8 bits) (8 bits) (8 bits)
L
(8 bits)
H02
(8 bits)