Read Holding Register (Reading Data Of Holding Registers) (H03 Or 03); Query Message Setting; Content Of Normal Response - Mitsubishi Electric A800-E Instruction Manual

(N) Operation via communication and its settings
Read holding register (reading data of holding registers) (H03 or 03)
• 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
f Starting address
g No. of points

• Content of normal response

Message
h Byte count
i Data
Example) Read the register values of 41004 (Pr.4) to 41006 (Pr.6) from slave address 17 (H11).
Query message
Transaction Protocol
identifier identifier
H00
 
(8 bits)

A given value is set.
Normal response (Response message)
Transaction Protocol
identifier identifier
H00 H00
 
(8 bits) (8 bits)

The values are the same as those in the query message.
Read value
Register 41004 (Pr.4): H1770 (60.00 Hz)
Register 41005 (Pr.5): H0BB8 (30.00 Hz)
Register 41006 (Pr.6): H03E8 (10.00 Hz)
42
PARAMETER
c. Length
field
L H L
(8 bits) (8 bits) (8 bits)
c. Length
field
L H L
(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 H03.
Set the holding register address from which to start reading the data.
Starting address = start register address (decimal) - 40001
For example, when start register address 0001 is set, the data of holding register address
40002 is read.
Set the number of holding registers for reading data. Data can be read from up to 125
registers.
The setting range is H02 to HFA (2 to 250).
Twice the number of reads specified by (g) is set.
The amount of data specified by (g) is set. Read data is output Hi bytes first followed by Lo
bytes, and is arranged as follows: data of start address, data of start address+1, data of
start address+2, and so forth.
Length
field
H00 H00 H06
(8 bits) (8 bits) (8 bits)
Length Unit
field identifier
H00 H09 H11
(8 bits) (8 bits) (8 bits)
d. Unit
e. Function
identifier
H03
(8 bits)
(8 bits)
d. Unit
e. Function
identifier
H03
(8 bits)
(8 bits)
Description
Description
Unit
Function
identifier
H11 H03
(8 bits) (8 bits)
Byte
Function
count
H03 H06 H17
(8 bits) (8 bits) (8 bits)
f. Starting
g. No. of points
address
H L H
(8 bits) (8 bits) (8 bits)
h. Byte
i. Data
count
H L ...
(8 bits)
(n  16 bits)
(8 bits) (8 bits)
Starting
No. of points
address
H03 HEB H00
(8 bits) (8 bits) (8 bits)
Data
H70 H0B HB8 H03
(8 bits) (8 bits) (8 bits) (8 bits)
L
(8 bits)
H03
(8 bits)
HE8
(8 bits)