Mitsubishi FX3U Series User Manual page 39

FX Series Programmable Controllers
3U
User's Manual - MODBUS Serial Communication Edition
Special Data
Register
CH1 CH2
D8415 D8435
D8416 D8436
D8417 D8437 Not used
D8063 D8438
Name Valid
Defines the device range that is used to store the
communication state (event & error counter and/or event log).
Bit No.
b0
b1-b3
Communication
b4
Status
M,S
Information
b5-7
Setup
b8
b9-b15
One MODBUS event is one byte so one 16 bit register will hold
two events. For further details refer to Subsection 9.5.1.
Note: For Event and Error Counter details refer to Section 6.4.
Defines the PLC head device address of the device block that
will store the communication status information.
Counter values occupy 10 devices and the event log requires
33 devices. Therefore if both are displayed a total of 43 devices
are required.
According to these rules, the maximum valid range will be:
Communication For D:
Status Device M, S Counter only: 0-7990 (i.e. D8415 / D8435 = 01H)
Range Setup Log only: 0-7967 (i.e. D8415 / D8435 = 010H)
Log and counter: 0-7957 (i.e. D8415 / D8435 = 011H)
For R:
Counter only: 0-32758 (i.e. D8415 / D8435 = 0101H)
Log only: 0-32735 (i.e. D8415 / D8435 = 0110H)
Log and counter: 0-32725 (i.e. D8415 / D8435=0111H)
Note: If the above mentioned rule is violated neither counter
-
In the event of a communication error this register holds the
error code corresponding to the error occurring during the
MODBUS communication.
Special clear conditions:
Communication
M, S 1) Power on
Error Code
Note: In the event of a Ch1 error MODBUS communication
6 Related Devices and Communication Status
Detailed description
Name
0 (bit = OFF)
Event and error Counter values
counter are not stored
Not used
Event log Event log is not
*Slave Only stored
Not used
Communication
status storage D-register
device type
Not used
nor event log is stored and an error is generated.
-
error '6321' will be stored in D8063. In the event of a Ch2
MODBUS communication error '3821' will be stored in
D8438.
6.1 Special Data Registers
R / W
Contents
1 (bit = ON)
Counter values
are stored
Event log is
stored
R,W
R-register
R,W
-
R,W
35
1
2
3
*1
4
5
6
*1
7
8
9
*1
10