Filter
Top Products
Chapter 8 Communication Functions
8-62
8.3.4 Instruction and example
1) MODBUS communication instruction(MODCOM)
Available device Flag
Instruction
M P K L F T C S D
#
D integer
No. of
steps
Error
(F110)
Zero
(F111)
Carry
(F112)
Ch
○
S1
○ ○ ○ ○ ○ ○ ○
○ ○
S2
○ ○ ○ ○
○ ○
○ ○
S3
○ ○ ○ ○
○ ○
○ ○
7
○
Ch Designated communication channel
S1 Device which is registered communication parameter
S2 Device which stored communication data
Error
(F110)
Error flag turns on when designating area is over
and the instruction isn’t executed
S3 Device which stored communication status
■ MODCOM Ch S1 S2 S3
(1) Example program
• Designate slave station No. , function code,.address, No. of reading
• When input condition(M0020) turns on, MODBUS communication starts.
• Receiving data are stored D1000, and communication status is stored to M100
• When operates as slave, MASTER-K120S responses to master station without commands. And When operates as master,
MASTER-K120S sends data in S1 with MODBUS protocol at rising edges of execution condition.
MODCOM
MODBUS communication
Flag
Designation