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Easy PLC Link

PLC Link (PLC to Temperature Controllers)

Happy new year 2013 for you all.
We decide to start this new ear with a new chapter of the PLC-Link series, I hope you like it!

As we see on the other chapters PLC to PLC and PLC to VFD, PLC Link is a method to easily communicate with Delta devices based on RS485 Modbus.
Because we already did it PLC and VFD, today we┬┤ll do it with Temperature controllers.

1. Netwrok Structure:
Communication is RS485, so follow the twisted pairs recommendations when possible.
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2. DTC Configuration:
First you have to setup the communication protocol as the PLC (9600,7,E,1 ASCII)
Second, remeber to change to 1 the parameter “Communication write-in selection”

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3. PLC Software:
Step 1 -> Set up communication protocol
Step 2 -> Set the number of register to be read/write (Check manual to understand the D1436 and D1452 special register meaning).
Step 4 -> Select the registers to be read/write (H4700 = Present Value; H4701 = Set Value)
Check the following Table for DTA and DTB
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For DTC or DTD jus follow the DTC manual table
Step 5 -> Enable PLC-Link

Do not hesitate to download the below examples
PLC LINK COM2 (PLC – DTC) and PLC LINK COM2 (PLC – DTA).dvp (Tested by DDC Automation)

Special Thanks to DDC Automation from UK for this example
Let us know your experience

PLC Link (PLC to VFD)

PLC-Link is not only a tool to exchange data between PLC’s.
With PLC-link you can also share memory space with a servo, inverter, temperature controller, etc…
In this case I would show you the procedure to do it with VFD-E series drive.

The advantage of this method agains the “sending frames one” is that you don’t need to program and trigger one frame for every value read or write to the slave.
With this method, you only have to configurate the communication, and you will have any Slave value in your master buffers.
follow the next steps:

1. Hardware
use exactly the same advices as the PLC-VFD communication post.

2. Decide the protocol to be used.
And write it on a post it in front of you. In this case we use protocol Modbus ASCII, 9600 baud,7,Even,1

3. Inverter configuration (almost same as PLC-VFD communcation post)
The important think on this step is get ready the inverter to receive orders from RS485 interface, so depending the inverter the values are going to be different. In this example I use VFD-E.
Check the parameters If you are going to use another inverter.

2.00 = 3
Source of First Master Frequency Command
3: RS-485 (RJ-45) communication

2.01 = 3
Source of First Operation Command
3: RS-485 (RJ-45) communication. Keypad STOP/RESET enabled.

9.00 = 2
Communication Address
in my example 2

9.01 = 1
Transmission Speed
3: Baud rate 9600bps

9.04 = 1
Communication Protocol
0: 7,E,1 (Modbus, ASCII)

4. PLC Software
In this case I recommend to have the manual opened, because basically is a matter to configure the PLC-Link special registers properly.

D1399:ID address of the first slave
D1434:Number of consecutive registers to be Read (by the master)
D1355:First register direction of the slave to be Read (H2102 = Frequency command)
D1450: Number of consecutive registers to be Write (by the master)
D1415: First register direction of the slave to be Write (H2001 = Frequency command)
D1480:Readed values Master Buffer (Slave 1)
D1496:Writed values Master Buffer (Slave 1)

To find what register I need to edit in each case, look in the manual for any of those registers, and look for the proper one.

And Check the following program and test it.
PLC Link COM2 (PLC – VFD)

I’m pretty sure that system will save you a lot of time and efforts.

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