IAI America REXT - Manual (Page 197)


Part 1 Specification
Chapter 3 Gateway R unit
173
Part 1 Specification
3.9.4 Function Block
3.9.4.1 Dedicated ROBONET Function Block
(1) Overview
IAI provides a dedicated function block for ROBONET systems.
It is called “ROBONET Gateway Modbus Cyclic Communication FBL” (ROBONET GW).
This function block performs the following operations between the PLC and ROBONET gateway (Modbus gateway
mode):
x Read gateway status signals, response commands and axis data cyclically
x Write gateway control signals, request commands and axis data
A conceptual diagram of data exchange between the PLC and ROBONET gateway is shown below.
Function block parameters are set to associate the memory areas of the gateway unit with the I/O memory of the PLC
based on 1:1 address correspondence. The function block constantly performs data exchange, but only between the PLC
I/O memory and gateway unit memory whose addresses have been associated.
Accordingly, the ladder sequence only needs to access the PLC’s I/O memory associated with the gateway unit memory,
as if accessing the gateway unit memory directly.
Since there is no need to use a ladder sequence to create communication messages to be sent, a desired ladder
sequence can be created without a need to consider serial communication.
PLC I/O memory Serial communication unit
(SCU)
Gateway unit’s
memory areas
PL
C
la
dd
er
s
eq
ue
nc
e
Parameters
Function block
The memory areas of
the gateway unit vary
depending on the
number of connectable
axes and operation
mode.
Parameters
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