Introduction
This chapter explains the communications ability of the CLICK PLUS PLC system for
exchanging data between the PLC unit and other connected serial devices. It covers:
• Electrical connections used for communications
• Networking routing between the PLC and other devices,
• Setting the port communication parameters,
• Selecting the protocols and the available data addressing types to use, and
• Ladder logic program instructions that make it all work together.
All CLICK PLUS PLCs have a built-in micro-B USB port for programming.
The C2-01CPU and C2-03CPU have an RS-232 port, designated Port 2. The port uses a 6-pin
RJ12 phone type jack. It is a general purpose port, user configurable, with its communication
parameters within CLICK Programming Software, C0-PGMSW. Port 2 can be used as a
Modbus RTU master or slave protocol device, or handle ASCII data In or Out (ASCII stands
for American Standard Code for Information Interchange and defines a character encoding
method for text that is used in computers and other communication devices. Details can be
found by doing a search for ASCII on the internet).
The C2-03CPU also has a 3-pin RS-485 port, designated Port 3. Like Port 2, Port 3 is a
general purpose port with its communication parameters being user configurable from the
programming software. Port 3 can be used as a Modbus RTU master or slave protocol device,
or handle ASCII data In or Out.
The C2-01CPU and C2-03CPU have a built-in Ethernet communications port.
The C2-02CPU and C2-03CPU have an antenna port capable of both Bluetooth and WLAN
communications.
The CLICK PLUS PLCs can be networked to other CLICK PLCs, data input devices (barcode
readers, weight scales, etc.), and/or data output devices (serial printers, serial text displays, etc.).
It is also possible to network the CLICK PLUS PLC to other 3rd party PLCs and devices that
have the ability to communicate using the Modbus RTU and TCP protocols.
The final part of the PLC Communications chapter contains explanations and examples of the
various ways the Send and Receive programming instructions can be used to perform Modbus
RTU protocol and ASCII data communications between devices.
There are three different data addressing types that can be selected when using the Modbus
RTU protocol from the Send and Receive instructions. They are, CLICK addressing, Modbus
984 addressing, or Modbus HEX addressing. The CLICK addressing makes it convenient
to exchange data between CLICK PLCs. The other addressing choices are selected based on
the Modbus protocol addressing the networked devices are using. For details on the Modbus
protocol, visit www.modbus.org.
NOTE:
The Modbus RTU Master is identified as the device that controls the exchange of data between
itself and any connected slave device. There can only be one master on the network. When the CLICK
PLC is the master, it is easily identified. It will be the PLC in the network with the Send and/or Receive
instructions using the Modbus protocol in its ladder logic program.
CLICK PLUS PLC Hardware User Manual, 1st Edition, Rev. B – C2-USER-M
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Chapter 4: PLC Communications
