User Communication Overview - IDEC FC4A-C10R2 User Manual

17: U
SER
Introduction
This chapter describes the user communication function for communication between the
with an RS232C port. The
tion to and from external devices.
Upgrade Information
Upgraded CPU modules of slim 20-I/O relay output types and 40-I/O types can also use the user communication through
the RS485 port and three additional BCC calculation formulas; ADD-2Comp, Modbus ASCII, and Modbus RTU. Applica-
ble CPU modules and system program version are shown in the table below. For the procedure to confirm the system pro-
gram version of the CPU module, see page 29-1.
CPU Module
RS485 User Communication
Compatibility
User Communication BCC
Upgrade
(ADD-2Comp, Modbus ASCII,
and Modbus RTU)
Using the RS485 user communication, the
devices.
The upgraded CPU modules can use three new BCC calculation formulas of ADD-2comp, Modbus ASCII, and Modbus
RTU for transmit instructions TXD1 and TXD2 and receive instructions RXD1 and RXD2. Use
higher to program the new BCC. For calculation examples, see page 17-36.
New BCC Calculation Formulas
BCC Name
Add the characters in the range from the BCC calculation start position to the byte immediately before
ADD-2comp
the BCC, then invert the result bit by bit, and add 1.
Calculate the BCC using LRC (longitudinal redundancy check) for the range from the BCC calculation
Modbus ASCII
start position to the byte immediately before the BCC.
Calculate the BCC using CRC-16 (cyclic redundancy checksum) for the range from the BCC calculation
Modbus RTU
start position to the byte immediately before the BCC. The generation polynomial is: X

User Communication Overview

The user communication mode is used for linking the
puter, modem, printer, or barcode reader.
The all-in-one 10-I/O type CPU module has one RS232C port. The 16- and 24-I/O type CPU modules have one RS232C
port and port 2 connector as standard. By installing an optional RS232C communication adapter (FC4A-PC1) to the port 2
connector, the 16- and 24-I/O type CPU modules can communicate with two external devices simultaneously.
Every slim type CPU module has one RS232C port. An optional RS232C communication module can be attached to any
slim type CPU module to use port 2 for additional RS232C communication. When an optional HMI base module is
attached to a slim type CPU module, an optional RS232C communication adapter can be installed to the port 2 connector
on the HMI base module.
User communication transmit and receive instructions can be programmed to match the communication protocol of the
equipment to communicate with. Possibility of communication using the user communication mode can be determined
referring to the user communication mode specifications described below.
C
OMMUNICATION
uses user communication instructions for transmitting and receiving communica-
MicroSmart
FC4A-C10R2
FC4A-C10R2C
—
MicroSmart
« FC4A M
I
NSTRUCTIONS
All-in-One Type
FC4A-C16R2 FC4A-C24R2
FC4A-C16R2C FC4A-C24R2C
204 or higher 204 or higher
CPU module can communicate with a maximum of 31 RS485
Description
MicroSmart to an RS232C communication device such as a com-
S U ' M
ICRO MART SER S ANUAL
and external devices
MicroSmart
Slim Type
FC4A-D20K3
FC4A-D20S3
204 or higher
WindLDR
»
FC4A-D20RK1
FC4A-D20RS1
FC4A-D40K3
FC4A-D40S3
202 or higher
ver. 4.40 or
16 15 2
+ X + X + 1.
17-1