how to configure modbus using LabVIEW?

[Nishant]

Mr. Srinivas,

             Here i m sending it again, but again it wont be visible, wat you do is whenever you open the link, right click on the picture, and click on save picture as and store it anywhere in your desktop, and from there open it and it if again is not visible then make it to 100% resolution and then you can see it clearly.

Thanks,

Nishant

[MichaelChaney]

Hi Nishant,

The library that is available from our website is for LabVIEW 7.1.  The files and instructions I posted are for anyone using LabVIEW 8.0

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71&p_...

[Anonymous]

Michael C wrote:
> Hi Nishant,
> The library that is available from our website is for LabVIEW 7.1.&nbsp; The files and instructions I posted are for anyone using LabVIEW 8.0<a href="http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71&amp;p_node=DZ52363&amp;p_source=External" target="_blank">http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=F1582737BACF5CA8E0340003BA7CCD71&amp;p_node=DZ52363&amp;p_source=External</a>
> &nbsp;

Did anybody try to set outputs of
(AutomationDirect.com) Direct Logic 05 PLC directly
from a LabVIEW program using NI Modbus library? I have
a dead simple question: What "Starting Address" do I
feed to "MB Serial Master Query.vi" to set the
outputs?
The DL 05 manual is confusing about this. I managed to
read the inputs using the same "MB Serial Master Query.vi" with
function 2
(Read Discrete Inputs) and address 2048, but can't set
the outputs with function 15 (Write Multiple Coils) or any
other. With some addresses it sets some coils OK (you
can tell, because this VI reads them back as well),
but, apparently, those are not the output coils
(output lights don't switch)!

[Anonymous]

Did anybody try to set outputs of
(AutomationDirect.com) Direct Logic 05 PLC directly
from a LabVIEW program using NI Modbus library? I have
a dead simple question: What "Starting Address" do I
feed to "MB Serial Master Query.vi" to set the
outputs?
The DL 05 manual is confusing about this. I managed to
read the inputs using the same VI with function 2
(Read Discrete Inputs) and address 2048, but can't set
the outputs with 15 (Write Multiple Coils) or any
other. With some addresses it sets some coils OK (you
can tell, because this VI reads them back as well),
but, apparently, those are not the output coils
(output lights don't switch).

[Srinivas Kharsada Patnaik]

hello nishant,

thanx 4 ur active reply.

i want to know about "class specifier constant".what is the use of this one?

can you let me know what is its significance n how/where to use this one?sorry, i am trying 2 learn labview.........so that whatever doubt comes,i m askin u.

thanks

[Nishant]

Hello Mr. Srinivas,

               Can u pls explain me something more about ur application of class specifier constant, where r u using it? so i can explain u more about that.

Thanks,

Nishant

[Srinivas Kharsada Patnaik]

actually i found it in a certain example which is already with LabVIEW 7.1.

its an example related to Queue control.

Its in Queue.llb library named Queue Control Reference Info.vi

Thanks

[Donald]

---

@Anonymous wrote:
Did anybody try to set outputs of (AutomationDirect.com) Direct Logic 05 PLC directly
from a LabVIEW program using NI Modbus library? ... With some addresses it sets some coils OK.

---

Anonymous,

I haven't tried the NIModbus library (yet), and I tend to only work with holding registers (not coils) in Direct Logic CPUs, but  2048/2049 does seem to be the correct starting address for the output coils (Y0 etc.) from all the docs I've got.

Couple of questions:

1) What position is the PLC's Mode switch in? STOP, TERM, or RUN?

2) With what addresses does it set "some coils OK"?  Have you tried writing to some internal/memory coils (C0-C777, starting Modbus addr 3072) that aren't used in your PLC program?

[Anonymous]

OK, it works now, but writing works only when the PLC is in the Run
state and the switch is in Term. Looks like reading inputs works in all
modes and switch positions though. I wonder if I can at all write to
the outputs when the switch is in Run. Because the PLC manual warns
that after the supercapacitor discharges when the power comes back on
it is unknown whether it will go into Run or Program mode. So it is
highly desirable to be able to write to the inputs with the switch in
Run.

[Tushar_Jambhekar]

Hi srinivas

we are in the Modbus Datalogger development for quite a long time now. and we have lot many of the shelf applications available with us. if you are interested in complete solution. please contact me on 09823015765.

we can provide you the apllication accustomed for you needs along with the source code.