Communication & Networking |Micro PLC - Low Cost Programmable Logic Controller

1. What Communication Ports Do My TRi PLCs Come With?

Fx-series	1 RS232 port, 2 RS485 ports (independent), and 1 Ethernet port
FMD series	1 RS232 port, 1 RS485 port (independent), and 1 Ethernet port
Nano-10	1 RS485 port and 1 Ethernet port
EZWire1616	2 RS232 ports, 1 RS485 port (independent), and 1 Ethernet port
E10-npn+	1 RS232 port reconfigurable as RS485 by jumper
E10-Relay+	1 RS485 port and IDC10 connector for external opto232 adapter.

2. What Devices Can My TRi PLCs Communicate With?

The Fx-series PLCs are the most versatile when it comes to the number of devices they can connect to and number of ways in which they can connect. Besides the 3 independent serial ports, there is a built-in Ethernet Port, a socket for an XBEE radio module, and an IR receiver. The serial port connectivity is the same as for the FMD series, described below. The XBEE radio module, which is available from Digi International, enables Fx-series PLCs to interface to futuristic ZIGBEE wireless sensors and control modules.

The Fx-series, FMD series, and Nano-10 'Super PLCs' all have Ethernet built in, which provides the following connectivity options :

- Control & Monitoring via Internet
- Remote Programming & SCADA
- Built-in MODBUS/TCP Server
- F-Server for i-TRiLOGI & ExcelLink
- Up to 6 simultaneous Server connections
- Send Emails to report real-time events
- Connects to other 'Super PLCs'
- Connect to other Modbus/TCP servers

Although all TRi PLCs have built-in serial ports, only the Fx-series, FMD series, EZWire1616, and Nano-10 'Super PLCs' can be programmed to actively read/write to its serial ports. As such, these PLCs can be programmed to communicate with any RS232 or RS485 devices using ASCII or binary data (Nano-10 only has RS485). Each serial port can be configured from 300 to 230k4bps, 7 or 8 data bits, odd/even/none parity. Thanks to their built-in MODBUSprotocol engine, these PLCs can be used as MODBUS master or slave and communicate with 3rd party SCADA, HMI or RTUs (Read more at: http://www.tri-plc.com/modbus.htm)

The serial ports on E10 series PLCs are "slave" only and respond automatically to ASCIIhostlink commands sent by a host PC or an Fx-series/FMD series/EZWire1616/Nano-10 master PLC, but the PLC program for E10 PLCs is unable read/write to the serial port directly.

3. Can I Connect a Barcode Reader to My TRi PLC? Or Smartcard or RFID Reader?

It is very simple to read from a barcode or smart card/RFID reader if the barcode reader can be connected to the PLC using RS232. Most bar code readers return data as ASCII strings terminated by a Carriage Return (CR character, ASCII 13) so you can simply use the INPUT$(1) command to read the data from the COM1 port. The PLC keeps a 256 bytes circular buffer for incoming serial characters so you don't have to be monitoring the serial port all the time. As long as the data are read before the buffer overflows (i.e. more than 256 bytes are received) the buffered data will not be lost.

4. Can I Connect a 3rd-Party HMI (Human-Machine Interface) to My TRi PLC?

We recommend TRi's MD-HMI for a low cost, character text only HMI and we recommend KEPs MT8050iE (available directly from TRi) for a low cost touch screen HMI since it supports the TRi PLC native protocol. However, most third party touch panel HMIs that support the MODBUS protocol should work with the Fx-series, FMD series, EZWire1616, and Nano-10 PLCs.

Additionally, the Fx-series, FMD series, and Nano-10 PLCs can connect to Ethernet based HMI's via the built-in Ethernet port as long as the HMI supports the MODBUS TCP protocol.

5. How Can I Connect My PLCs to a Serial Comms Network?

All TRi PLCs now feature 1/8 power RS-485 interface which allow up to 255 PLCs to be networked to a master PLC or a host PC (via Auto485 or U-485 adapter), using very low cost twisted-pair cables. However, any Fx-series, FMD series, EZWire1616, or Nano-10 PLC may act as the network master of the serial comms network. The E10-npn+ PLCs are slave-only devices.

If a PC is used as the network master, then the programming software, TRiLOGI or WinTRiLOGI can select any of the networked PLCs using only the device ID for programming, monitoring and control all from a single point of attachment to the network.

6. What If My PC/Laptop Only Has USB Ports and no RS232 Port? Can I Use It to Program My TRi PLC?

There are many USB to RS232 converters in the market but we have reports that some of them did not work well for this purpose. We carry this type of converter, which is part # USB-RS232 and is made by Prolific. Here is the link to the product page on the TRi website :

http://www.tri-plc.com/USB-RS232.htm

We have also previously tested a BF-810 made by BAFO and one sold by www.serialio.com. Both units worked without problem in a Windows 98, Me and XP environment.

7. What Protocols Do TRi PLCs Support?

The Fx-series, FMD series, EZWire1616, and Nano-10 'Super PLC' families support many different communication protocols to allow maximum application flexibility. In addition to its own native set of ASCII based communication protocols, these PLCs also understand and speak the following protocols :

MODBUS ASCII mode compatible communication protocol.

MODBUS RTU mode compatible communication protocol.

OMRON Host Link Commands for the C20H PLC family.

YOUR OWN CUSTOMIZED protocol using TBASIC!

Additionally, the Fx-series, FMD series, and Nano-10 PLCs can communicate in the industry standard "MODBUS/TCP" protocol using their built-in Ethernet port.

8. What Does 'Web-Enabled' Mean for the TRi 'Super PLCs'?

The TRi 'Super PLCs' with Ethernet built in (Fx-series, FMD series, EZWire1616, and Nano-10 PLCs) can be directly connected to a network for instant connection across a LAN or over the Internet with port forwarding setup. Program transfers and online monitoring can be done locally or remotely over Ethernet with the TRiLOGI programming software. Additionally, various types of 3rd party monitoring/control software can communicate with these PLCs over Ethernet using the Modbus TCP or TCP/IP protocol. Since the PLC Ethernet ports include a built-in Web server, Java Applets and HTML Web pages can be stored, which allows the PLC data to be accessed from standard Web browsers on a PC and many smartphones (HTML only since Applets aren't yet supported on smartphones).

9. How May I Take Advantage of the Web-Enablement of the Super PLCs?

Troubleshoot equipment operation remotely

To load new programs remotely without providing source code to the user on the field (may be important to OEM equipment manufacturer)

For development of SCADA-like, centralized or remote monitoring applications at a cost that only very high-end applications could justify in the past.

Instant access to PLC data over the Internet for remote alarm monitoring and equipment control.

Email notifications

Data logging to a remote server

10. What Security is There to Prevent Unauthorized Access of My PLC?

The server built in to the 'Super PLCs' with Ethernet (generally referred to as FServer) as well as TLServer can be configured to require a username and password for login when communicating with the PLC over Ethernet, which enables user authentication.

The FServer (as well as TLServer) also divides the user access levels into "programmer", "user" and "visitor", and only users given the "programmer" access right can program the PLC. Users who are given "visitor" access right can only monitor the PLC status but would not be able to affect its operation. This allow finer control of the access to the PLCs.

You may setup firewall in the network router to disable access to the FServer or TLServer when external access from the Internet is not required.

Only the FServer (including the Modbus TCP server) has the additional security feature of "Trusted IP", which allows specific IP addresses to configured as "safe" and all other IP's will be ignored.

11. What Options Are There to Send an Email From the PLC?

Here are the different ways to send emails with TRi PLCs currently.

1. Send Email from the PLC with the EMAIL Tag

You can send an email with the <EMAIL> tag in your PLC program, which uses the Ethernet port. The help file is referring to the old method where the PLC had to connect to a PC via serial port and use TLServer to send an email because Ethernet wasn't built in at that point.

In addition to a static IP address in the PLC, you will need to configure the gateway address, which is the IP address of your network router and the SMTP server, which is the address of the mail server that you are using. More information on these settings can be found in section 2.1.2 and 2.1.3 of any Super PLC user manual.

Once those settings are configured, you will need to refer to chapter 2.3.3 for information on sending an email from the PLC. There is also a sample program called TestEthernet.PC6 that has an example for sending emails. This program can be downloaded at the beginning of chapter 2.3 in the notes box.

The user manuals can be downloaded here: http://www.tri-plc.com/documentlist.htm

2. Send Email from the PLC via Remote Ethernet connection to TLServer

The <EMAIL> tag in TRiLOGI is not able to implement authentication that is now required by most email servers, but TLServer also has an email function that is able to handle authentication. Here is a link to a forum post on our Website that explains how to do a remote connection to TLServer for sending an email through TLServer. In this case you will need TLServer running on a PC with Internet connection continuously and the PLC will make a connection to TLServer over Ethernet in order to initiate an email send indirectly (similar to the old method mentioned above except using Ethernet rather than serial).

http://www.tri-plc.com/yabbse/index.php?board=2;action=display;threadid=1608;start=msg5309#msg5309

3. Send Email directly from the PLC using a Soft Coded Method in the PLC Program

Some users didn't want to send emails indirectly through TLServer, so we have also created a workaround method that allows you to send authenticated emails directly from the PLC.

At the bottom of the above forum post, there is an application note package with two sample programs that allow you to send authenticated emails directly from the PLC. The programs use the Telnet method for communicating with an SMTP server and sending an email, which is actually the same process used by the <EMAIL> tag, but with a slightly different command that may work for servers that require authentication. You will need define your SMTP server and Email account settings (including authentication username/password) in the Send_Email custom function.

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