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Am using Red Lion display, model PAX2D, with an option card for RS232, and want use Modbus RTU to display values from a V350.

 

I can get successful comm. by connecting RXD from display to RXD(pin 3) on V350, and TXD to TXD(pin 4) with no ground.  As soon as common (pins 2 or 5 on V350) are connected to RS232 common on display, comm. halts.

  

By wiring as above, I can read values from registers in the display, but they seem to be random numbers, not anywhere close to what they should be.  For instance when reading register 40483(display baud rate), a value of 8960 is returned no matter what the baud rate is actually set at, and I would be expecting to see a number from 0 to 5 for the 5 baud rates available on the display.

 

PAX2D display manual:  http://www.redlion.net/Products/Groups/Counter/Rate/PAX2D/Docs/04038.pdf

 

PAX2D Modbus table:   http://www.redlion.net/Products/Groups/Counter/Rate/PAX2D/Docs/04045.pdf

 

PAX2D RS232 option card manual:    http://www.redlion.net/Products/Groups/PAXOptionCards/PAXCDC1,2/Docs/12018.pdf

 

V350 program:   https://www.dropbox.com/s/86hmdjtqg0qdkqd/Test%20Display.vlp

 

 

I talked with Red Lion tech support to make sure display setup is correct.   Appreciate any help!

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Hello ahoover

 

Without reading the red data station manuals you mention that TXD from Vision is connected to
TXD from red lion and RXD  from Vision to RXD from red lion.

 

But when I’m not mistaken TXD from Vision(transmit data) should be connected to RXD(receive data) from Redlion and RXD Vision(receive data) to TXD (transmit data)from Red lion. But I assume that you have already tried this?

 

 

Regards
Henny

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This is also what I understand TXD from one unit has to connect to RXD from the other unit, and I have tried that.  It seems very strange to me that wiring as I mentioned above can communicate albeit with undesired results.

 

ahoover

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This is also what I understand TXD from one unit has to connect to RXD from the other unit, and I have tried that.  It seems very strange to me that wiring as I mentioned above can communicate albeit with undesired results.

 

ahoover

Hello ahoover

 

Perhaps the info on this site will help you any further?

 

http://www.lammertbies.nl/comm/cable/unitronics-rj11.html

 

Regards

Henny

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Thanks, but have used that site already.   Am pretty sure I have tried the correct wiring connections with no success.

 

ahoover

Hello ahoover

 

I assume that you also have the correct serial settings in Red lion so

Baud rate 19200,8 data bits,1 stop bit and parity NONE and de communication protocol is set to Modbus RTU and slave address is 2.

For communication adaptor the MJ10-22-CS76 should be the correct one cost about 12 euro.

I used it for communication between a V570 and a Brady BBP11 label printer.

 

If the V350 has two serial ports did you also try with com 2?

Are the dipswitches for comport in V350 correct set for RS232(factory setting) and not RS485 could be if the unit was used before for another purpose?

 

What is the value of MI600 when you try to read a register, should be zero if communication  is correct otherwise you can find info in visilogic help file.

Did you also make use of the visions info screen to monitor the data and settings from the serial port?

 

Hope these suggestions can help you any further?

 

Regards

Henny

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The communication I have been getting as specified above(tx to tx & rx to rx) appears to simply be a loopback, the same results happen when connecting tx & rx wires together.  I did not realize this was possible.  So the problem remains of getting the correct wiring connection to work.

 

ahoover

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When I use serial monitor on V350, this is what I see:   Tx: 02 03 9E 22 00 01 0B DB         Rx: 02 03 30 FC    The DIP switches are set to RS232.  The Modbus function status goes to "4" for 3 times then goes to "5".

 

ahoover

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When I use serial monitor on V350, this is what I see:   Tx: 02 03 9E 22 00 01 0B DB         Rx: 02 03 30 FC    The DIP switches are set to RS232.  The Modbus function status goes to "4" for 3 times then goes to "5".

 

ahoover

 

Hello ahoover

 

I assume that you have constructed the communication cab le yourself by using a 4 wire telephone cable with RJ11 connecter at one side and a DB9 male connecter at the other side ?

If you have a spare DB9 Female connecter and replace it with the DB9 male and connect it like a programming cable so that you can go online to the V350 with visilogic?

In this way you know if you cable is correct.

 

Or do you have a working programming cable that you can use to figure out that the RS232 port on the Vision is working.

In your first mail you mention that communications stops if you connect pin 5 GND db9 to pin 2 or 5

From V350.

Did you also test if you connect pin 5 GND db9 to pin 2 and 5 from V350?

 

Here is also a link to a Unitronics manual about communication.

 

http://www.unitronics.com/Downloads/Support/Technical%20Library/VisiLogic%20Software/Software%20Manuals/VisiLogic%20-%20Communications.pdf

 

 

Unfortunately I don’t remember how I connected my 4 wire telephone cable to a DB9 male connecter to set up the communication between a V570 and a Brady BBP11 label printer because later when the project was finished I used a Unitronics RJ11 programming cable with a MJ10-22-CS76 adapter.

If it doesn’t help perhaps you can contact Unitronics support so that they can help you further otherwise you never can get your project finished.

 

 

Have a good weekend.

 

Regards

Henny

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I have constructed the cable using a standard Unitronics programming cable with one end cut off, the wires stripped & fastened to screw terminals on the Red Lion RS232 card.  The option card I am using does not have a DB9 connector.    Modbus comm works flawlessly with a second V350.

 

I have been in contact with Unitronics tech support over the last couple days, but at this point we have not gotten any breakthroughs.

 

I appreciate the time & effort!

 

ahoover

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I have constructed the cable using a standard Unitronics programming cable with one end cut off, the wires stripped & fastened to screw terminals on the Red Lion RS232 card.  The option card I am using does not have a DB9 connector.    Modbus comm works flawlessly with a second V350.

 

I have been in contact with Unitronics tech support over the last couple days, but at this point we have not gotten any breakthroughs.

 

I appreciate the time & effort!

 

ahoover

Hello ahoover

 

So you use the PAXCDC20 RS232 output card with terminal block and not the PAXCDC2C with the DB9 port?

While Modbus communication works between the V350 you using and another one the problem is definitely not the V350 hardware.

 

Then in the PAX2D display manual at page 2 there is a note about Modbus communication.

1. For Modbus communications use RS485 Communications Output Card and configure communication (tYPE) parameter for Modbus

 

So perhaps Modbus is not possible with PAXCDC20 RS232 output card and can only be done with

RS485 module PAXCDC10 or PAXCSC1C?

At page 4 of the PAX manual(first link in your first posting) you find how to set the protocol to modbus RTU but I assume that you already have this setting correctly done?

 

Also  found a datasheet on the internet about the optional comm cards.Reading this at page 6 using a PAXCDC40 - Modbus (Terminal)

http://www.farnell.com/datasheets/1748232.pdf

 

 

The manual of the PAXCDC20 RS232 output card also doesn’t mention Modbus communication only serial ascii communication and no protocol setting can be find to change between ascii or Modbus RTU.

 

If this is true and you want to stay to you current configuration then you have to make a new program for the V350 using the FB protocol to send and receive ascii characters over the RS232 line.

and otherwise get in contact again with Red Lion to find out about the different output cards and possible communication protocols.

 

Regards

Henny

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Henny,

 

It appears you are right about Modbus RTU only being available with RS485, I missed that one important line in the manual. :(   It's a bit disappointing in Red Lion tech support, as I told them my hardware and what I'm trying to do, and they never pointed this out.

 

I set the display to RCL comm. & used a protocol send function to write a value to counter A which is working fine.

 

 

Thanks a lot for your help!!

 

ahoover

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Henny,

I tried to post this morning but it did not show up, so will try again.

 

It looks like you are correct, Modbus RTU can only be used with RS485, I missed one important line in the manual.  :wacko:    I am kinda disappointed in Red Lion tech support, as I gave them all details on hardware & what I'm trying to do, they did not point out to me this is not possible using RS232.

 

I have gotten this working now by setting the display comm to RCL & using a protocol function block to write a value to counter A on the display.

 

Many thanks!!

 

ahoover

Red Lion PAX2D with Serial RLC Comm.vlp

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Henny,

I tried to post this morning but it did not show up, so will try again.

 

It looks like you are correct, Modbus RTU can only be used with RS485, I missed one important line in the manual.  :wacko:    I am kinda disappointed in Red Lion tech support, as I gave them all details on hardware & what I'm trying to do, they did not point out to me this is not possible using RS232.

 

I have gotten this working now by setting the display comm to RCL & using a protocol function block to write a value to counter A on the display.

 

Many thanks!!

 

ahoover

Hello ahoover

 

No thanks

 

Good to hear that the communication works now between your V350 and Red lion PAX2D display.

 

Henny

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