Labview 8.20, Serial Modbus, and Despatch Oven Controller ... pointers for modbus master application?

[BEHajder]

Jqm,

I have attached the LabView example used to demonstrate communication with the Despatch Protocol Plus controller that I referred to in my previous post. At the time I posted it I was not at a location I could attach it from. This vi is written in LabView version 6.1.

If nothing else, this example should help you easily verify that your cables and Protocol Plus jumpers are correctly installed. You may have to change the hard-coded port setting from COM1 to what is correct for your PC, plus the baud rate and parity if you have changed the Protocol Plus default settings.

Good Luck!  - Brian

[jqm]

BEHajder,

I will give this a try today....hopefully things will run smoothly.
As an FYI the person that I was in contact with to at your company was the SR Product Support Engineer (D.B.),

Again Thank you for your time in this matter.
JQM

[Khalid]

JQM,

1. My Virtual Serial Port Kit settings are the default, which are the same as yours:

General Tab: Bitrate Emulation is DISSELECTED
Pinout: Full Handshake, Selected DTR to DCD

2. For the NIModbus VIs, these are still in LV7.1.1, but they open just fine in LV8.20 for me. And that's how I tested them. I can try and save a copy of these in LV8.20 for you if you wish.

Regards,

-Khalid

[jqm]

Khlad,

Yes, could you upload the 8.2 files...<<while I wait for National to update>>....


I tried redownloading the NIMODBUS71_80.zip again, retried, same problems....
????Maybe there is something flaky in my install of LV that is killing the app????


Thanks alot.

JQM

[Khalid]

I am attaching the NIModbus.llb. It's still in LV7.1.1 version (I can't figure out how to save a LLB in 8.20), but the VIs should open just fine in 8.20.

Hope this helps.

-Khalid

[Khalid]

I had a "duh" moment in the morning. Anyways, here's the NI Modbus.LLB saved in LabVIEW 8.20 version. Still works for me.

-Khalid

[jqm]

Khalid,

Thank you very much....
My testing has revealed 2 problems:
1) Belkin F5U409 USB-Serial ports (qty 2) ....there was something flaky with the driver installation.  Even though some of the hyperterminal testing would transfer files back and forth...there was something flaky with 1 of the 2.... (this showed up connecting to another device my company makes, the RS232 device would TX but not RX????)
2) Upon uninstalling and re-installing the drivers, AND using your NIMODBUS.lb for V8.20, the master/slave examples IS WORKING (along with the RS232 device my company makes)

I have tried to use BEHaider's sample code to connect to the DESPATCH OVEN (MODBUS COMM EXAMPLE) but it too does NOT work.  Upon Labviews conversion there were 2 alerts; an object created and an object deleted... I didnt notice anything flaky upon analysis of the block diagram..... I am beginning to think that there is an issue with my Labview installation (or a bug) ...

Khalid, could you be as kind as to download BEHajder's MODBUS COMM EXAMPLE and convert it to VERSION 8.20 , and repost for me.

Thank you for your time and patience.
JQM

[Khalid]

Hi JQM,

Since you got the Example Master/Slave to work with my version of 8.2 library, I am guessing there's something wrong with the other version you used earlier??

In any case, I am attaching Brian's VI saved for LabVIEW 8.20.

I noticed that Brian's VI uses Function Code 4 -- for reading Input Registers. So, I setup a Modbus Slave with an Input register 30001, and I was able to succesfully read the value from this Slave using Brian's VI.

Hope this helps.

-Khalid

Message Edited by Khalid on 10-12-2006 01:53 PM

[Rudi_N]

JQM:

I apologize for the delay in my response. Here is a link to where you can download the updated Modbus library for LabVIEW 8.2. I hope this helps and please do not hesitate to contact me if I can be of any assistance.

Best Regards,

Rudi N.
Applications Engineer