Mitsubishi QJ71MB91 User Manual

4
MODBUS(R) STANDARD FUNCTIONS
4.4 Read Coils (FC: 01)
4 - 18
1
OVERVIEW
2
SYSTEM CONFIGURATION
3
SPECIFICATIONS
4
MODBUS(R) STANDARD FUNCTIONS
5
FUNCTION
6
PRE-OPERATIONAL PROCEDURES AND SETTINGS
7
PARAMETER SETTING
8
UTILITY PACKAGE (GX Configurator-MB)
4.4 Read Coils (FC: 01)
Reads the status (ON/OFF) of one or more coils.
(1) Request message format (Master Slave)
(2) Response message format (Slave Master)
(When completed normally)
(When completed with an error)
* 1 Exception and error codes are stored in the buffer memory in the case of error completion.
Refer to the following for storage location, confirmation methods, and detailed contents.
Section 11.4
Figure 4.9 Read coils (Request message)
Figure 4.10 Read coils (Normal response message)
Figure 4.11 Read coils (Exception message)
Data
(L) (L)
Function code
Function
code
(01
H)
Head coil number
(0000
H to FFFFH)
Read points
(0001H to 07D0H)
(H)
(H)
Data
b0b1b2b3b4b5b6b7
Function code
Function
code
(01
H)
Number of
read bytes
n
Device data
1
Device data
n
(Number of read bytes n)
(Device data 1 to n)
Device data 1
Device data n
Bit device
storage order
0 : OFF
1 : ON
The read coil statuses are stored in order from low-order to high-order bits.
When the number of read points is not a multiple of 8, the excess bits turn to 0.
Data
Function code
(81
H)
Function code
Exception
code*
1

Mitsubishi QJ71MB91 Specifications

General

Brand	Mitsubishi
Model	QJ71MB91
Category	Controller
Language	English