How to log Type J Thermocouple using V570-57-T20B-J with a snap on IO V200-18-E2B

[Jean-Jacques Lubin]

I'm creating a new program for this system which is already wired up, the thermocouple is connected to the Port 2 of the V570.

How do I read the data from the port and for the data to be converted into Degrees Celsius.

Thanks

JJ

[Flex727]

If I'm not mistaken, the V200-18-E2B Snap-In module does not have thermocouple inputs. You'll need a V200-18-E3XB.

[Ausman]

Edited, I was stupid and didn't look at the description header!

cheers,

Aus

 

[Simon]

Hi JJ,

I have a few questions:

* When you say it is connected to Port 2 of the V570 - do you mean COM2?  Does the thermocouple have a Serial/Modbus interface?

* The post by Flex727 is correct, the E2B snap-in module doesn't take thermocouple inputs directly.  It would need a signal transmitter, typically this converts the thermocouple interface to 4...20mA current signal.

If you have a datasheet for the thermocouple and/or any photos of the device and the way youhave it wired up, please post.

[Jean-Jacques Lubin]

Hi Simon,

Thanks for the quick reply.

The equipment i'm working on has been wired by a previous company and we've been asked to re program the V570, to give them more options when they run their test.

The thermocouple type J is connected to a Shinko temperature controller BSC2R0006 which has a serial output which is connected to V570  Port 2 as shown on the photos below, which could be COM2.

The serial output is  4-20mA and type J thermocouple range is -200 to 1200 degC. I guess what i need to know if V570  port 2/com2 can read analog signal and how do we program on V570.

If you can help that will be greatly appreciated.

JJ

[Kikis]

Hi jean,

 

4-20mA is an analog signal and has nothing to do with the serial port.

IO-V200-18-E2B snap-in module can take 4-20mA analog input, but this is not the way you have to proceed.

 

From datasheet, i can see that Shinko's BSC2 temp. controller can communicate with external devices via RS485 using Modbus.

Most probably they used this protocol in order to read and write parameters (PV, SV) via V570.

Check the parameter values on the BSC2 to find out how serial connection is configured (communication protocol, speed, etc...).

You can also remove the snap in module and check the DIP switches on the V570 to see if COM port 2 was set to RS485.

 

Then we can provide more help.

 

 

[Jean-Jacques Lubin]

Kikis,

Yes Shinko's BSC2 temp. controller serial connection for Modbus ASCII start Bit 1, Data Bit 7, Parity Even, Stop bit 1, and communication speed 38,400.

V570 Com port 2is set to RS485.  What I'll need to know now is how to put this in the ladder diagram. 

Hope you can help me, Thanks

 

[Kikis]

Hello Jean,

 

Best way to understand how Modbus works with Unitronics is to watch the following webinar.

 

There are also a lot of Modbus  example programs included within Visilogic.

Your V570 will be the master in the network, so you need the Modbus slave address table of the BSC2 to select the parameters you want to read or write to.

 

[Jean-Jacques Lubin]

Kikis,

Thanks for the response, it did help.

 

 

JJ 

[Jean-Jacques Lubin]

Hello,

I'm still having issues to connect and read the "PV" value of the Shinko Temperature controller using Modbus Protocol. 

The parameters set are the following;

PLC - V570

Modbus ASCII
Communication speed 19200bps
Data bit/Parity 7 bits/Even
Stop Bit 1

Slave ID #65 and Slave address 0100H and I have change the dip switches to RS485 on V570

Shinko Temperature controller

Modbus ASCII
Instrument number 65
Communication speed 19200bps
Data bit/Parity 7 bits/Even
Stop Bit 1
Response time 10ms
See attached Shinko documents and a screen shot of the ladder diagram. When I try  to read PV value I’m getting an error message of no communication established (Status Message goes from 4 to 5).

I have been communicating with Shinko Japan and we have  checked my wiring and settings all seemed to be ok. But they mentioned that the PLC need to send this command 020401000000F9 CrLf,  This is where I'm not sure how do that. If you could help it would be greatly appreciated.

Regards

JJ

serial communication shinko remp controller.pdf

[Joe Tauser]

The command they told you to send is not a Modbus ASCII protocol command.   Modbus ASCII command strings all start with a ":" (hex 3A).  Based on the document, I tend to believe that's the Shinko native protocol

The help on RS485 can be misleading.  You don't have to use 65 as a slave  address.

I'd start over and set the instrument to address 2, Modbus RTU, 19200 8 data No Parity 1 stop (19.2 8N1).  Then set your V570 to match.

Post your code so we can drill into the COM init block.

Joe T.

[Jean-Jacques Lubin]

Joe,

I have done the changes you suggested,  which is good as now i'm not getting any error messages regarding communication as my status message is "0".

But the return value at "MI 23" is fluctuating between 0 and 1, I need the value to return the PV display of the shinko Temp. controller value of 23 degrees or whichever the PV display is.

As i'm logging that value into a Table and a Running curve. Attach is my code of my PLC program.

thanks for your help.

JJ

PLasticorder PL200 v12.vlp