dswaine

...

I am working with datasocket and OPC server. ...

In LabView I just want to be able to address a particular bit, not the entire byte.

Any suggestions would be greatly appreciated!

Apologies if I'm missing something but ...

If you're using frontpanel Datasocket connections: have you tried just linking a boolean/switch to a particular bit?

If you're using the Datasocket VIs: have you tried DataSocket Write Boolean.vi or DataSocket Read Boolean.vi (from ... \LabVIEW xx\vi.lib\platform\dataskt.llb).

...

I think I need OPC server/client software but would anybody have more specific information about the subject?

Mize,

You've got a lot of options and aren't necessarily limited to using OPC. A lot may depend on how many euros you have to spend.

A web search (example here) will bring up dozens of OPC servers for Siemens S7 and there are quite a few that make use of the "HMI Adapter" cable

I was hoping to avoid using an OPC. Find some drivers somewhere but....

You may want to take a look at the "S7-200 Programmable Controller System Manual"'s (6ES7298-8FA24-8BH0) chapter on using Modbus communication. If you can't find the manual on Siemens' site, there's a 2004 copy at mrplc.com.

As described in it, Siemens has an the add-on ($$) library that includes code for enabling Modbus on S7-200 CPUs. I've never used it, but if my impression is correct it will allow you to use the S7-200's serial port a Modbus slave.

If true that would enable the use of one of the more readily available Modbus drivers that have been written in LabVIEW.

Good luck with whatever route you take.

... Could anybody convert it to 6.0, please?

Conversion to v6.0 attached.

Download File:post-55-1132059125.vi

Does anybody know of a decent way to get rid of a loop (eg While or For) but keeping the G components and wires within the loop in the place they are? ...

Right clicking on the frame of While/For loops, Case/Sequence structures you can access the "Remove ..." command which I think (?) is what you're looking for. You can also Replace one loop with the other type; ditto for the structures.

... Why would NI build 2 products when one can do the job so it must be something in it to differentiate the 2 products, right?.

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There's history involved too. LabVIEW for Windows only came out in ~1992; before that it was LabVIEW for Macs (since '86) and LabWindows for DOS (since '87). There's a couple of articles in NI's old 'Instrumentation Newsletter' from the winter of 92/93 on making the choice between LabVIEW and LabWindows, and they boil down to the point(s) made by m3nth: preferred programming methodology.

A solution for LabView 6.0 would be ideal ...

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If my memory is correct, this was a relatively common problem in LV v6.0 which was fixed ... to a large degree ... in v6.0.1 or 6.0.2. The patch for v6.0.2 was/is free and is available here. There were glitches in LV6.02 as well, but they were definitely fewer.

Any ideas?

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There are several ways, but the one that came to my mind first was:

If you�re on Windows, over in the Example Code section at ni.com, there�s clipboard.llb.

With it you can do something like in the attached jpg.

If you search the Example Code section for �clipboard�, you�ll get several other hits for Vis (some ancient) that take the keystroke simulation approach.
 

Besides the links that ptit bras gave you, an excellent summary of available LabVIEW/Modbus options was put together by Khalid on the NI forum last year and can be found here.

Most, if not all, will work in LV6.1.

Things may have moved a bit in v7, but try YScale.Range. ... to access Increment, Minor Increment and Start. "Start" is the value of the first major gridline which (I think) defaults to a multiple of Increment.

Michael,

Apologies if I'm missing something, but does your question boil down to:

"How can I easily get discrete bit/boolean values from a U8?"

If yes, then the answer is: "Numeric>Conversion>Number to Boolean Array"

@ 0:10 EST 20040204:

Group: The Clash

Album: London Calling

I could not find a property inside a graph property node that would allow for the plot style change (e.g., changing from default "line" style to "point only" style).

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To get rid of the line, set Plot interpolation = 0.

Trying to work with date and time with this format:

  mm/dd/yyyy hh:mm:ss (This is the input I have)

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Hi Jose,

I'm assuming that this is a string input you're dealing with.

If so the 'Scan from String' and 'Date/Time To Seconds' functions can be used to obtain a numeric datetime. Attached vi (LV6.1) is variation of what I use. Convert the strings for the two times and then subtract.

Download File:post-55-1101928881.vi

I think "Front Panel Window >> State" was added in LV7 (or else I've been making life harder than need be).

In LV6.1, you can use the Windows management VIs that can be found in the lvwutil32 libraries available from:

NI KnowledgeBase

Minimize Window.vi and Maximize Window.vi in winutil.llb.

The programming on the PLC side can also have a significant effect on the update/communication rate limits. If the items/data registers you've configured tags for are scattered all over the PLC's memory map, the OPC server has to read a lot larger block of PLC data than it would if the items were contiguous.

There's mention of how the NI's Industrial Automation Servers are "optimized" to speed read/write operations somewhere in all the documentation that comes with LVDSC, but PLC communication protocols don't always lend themselves to much optimization.

You are from Pickering eh?  I don't suppose you are running v2.2 at that there nuclear plant are you? 

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No, I'm a stone's throw away (not that I actually plan to throw anything at the reactors ... might break a pipe).

For those with an historical interest: LabVIEW v2.2 on a Mac Classic.

Still gets used.