I need to read a modbus using labview - how?

[Denise Brown]

I need to read the modbus of a process gas chromotograph. I'd like to use labview since I am familiar with it and I use it in other parts of my application. I've found some German and Norwegian sites with Labview modbus VIs, but they all seem to require RS232 communication, and the people that put together my GC only allow communication with the modbus using RS422. So, I need to write a program using regular Labview VIs to read the modbus over RS422. I can probably figure it out eventually, but I'm crunched for time. Can anyone out there give me any idea of the problems I am going to encounter, how to go about this, etc?

[crelf]

G'Day Denise,

I'd personally use a third party driver - SEG has one called "BusVIEW" - you can review it here:

http://www.softwaretoolbox.com/store/item_pages/itempage_63.asp

I haven't used this driver specifically, but I have used the sister software (HighwayVIEW - for AB PLCs), and it worked fine. I'm not sure if it can handle 422 (I assume it does), but you might want to check the specs.

HTH!

cheers,
Christopher G. Relf
Christopher.Relf@mBox.com.au
Int'l Voicemail & Fax: +61 2 8080 8132
Aust Voicemail & Fax: (02) 8080 8132
NetMeeting Reflector: ils.kern.com.au

---
EULA
1) This is a private email, and although the views expressed within it may not be purely my own, unless specifically referenced I do not suggest they are necessarily
associated with anyone else including, but not limited to, my employer(s).
2) This email has NOT been scanned for virii - attached file(s), if any, are provided as is. By copying, detaching and/or opening attached files, you agree to indemnify the sender of such responsibility.
3) Because e-mail can be altered electronically, the integrity of this communication cannot be guaranteed.

[Denise Brown]

hey, chris,

thanks for your fast response. i ran across busview while i was researching, but i don't like buying software i know nothing about. thanks for the recommendation. it looks like busview will work, even though i will need an rs232 to rs422 converter.

[crelf]

G'Day Densie,

I must admit that I felt the same when looking at AB drivers - $US795 is a lot of money (especially when you convert it into Australian dollars!), but the development time it saved me (and therefre the company I was consulting to) was pretty huge, and well worth it. If you need more info about it, try contacting the guys from SoftwareWithRelish (they are the people that wrote the software, whereas SoftwareToolbox are the people that market it) - a good bloke to talk to is Andrew ( andrew@softwarewithrelish.com ) - he should either be able to answer any questions you have, or at least point you in the direction of someone who might be able to help.

Good luck!
Christopher

[Denise Brown]

hi, chris.
actually, here in texas we're supposed to say 'howdy' but i can't quite make myself use it seriously.
i found a demo copy of busview. it looks great. thanks for pointing me in that direction. i just found out that there might be some problems converting the modbus 422 signal to 232, so i need to talk to the guy you recommended to see what he thinks. but even if i can't use busview for this specific application, it's good to know it's out there. thanks for all of your help.

denise

[urs boegli]

Denise,
There are two labview drivers for modbus availible for free.
May be you have to adapt them, but it's not a big job.
You may google the adresses.
I think one can be found at www.air.nl

Urs Bogli

Denise Brown schrieb:

> I need to read the modbus of a process gas chromotograph. I'd like to
> use labview since I am familiar with it and I use it in other parts of
> my application. I've found some German and Norwegian sites with
> Labview modbus VIs, but they all seem to require RS232 communication,
> and the people that put together my GC only allow communication with
> the modbus using RS422. So, I need to write a program using regular
> Labview VIs to read the modbus over RS422. I can probably figure it
> out eventually, but I'm crunched for time.
Can anyone out there give
> me any idea of the problems I am going to encounter, how to go about
> this, etc?