How can I monitor 4 Stations independently?

[dVaughn]

Hello,

First off I would like to start by thanking anyone taking the time to read this as I am new to LabView and having trouble writing this program on my own even though I am using the examples and forums to guide me.

Background:

We have 4 indepent work stations that we would like to monitor using (1) NI PCI6254 and LabView 8.0. Each of these stations will have their own events/occurences to begin taking data from. We have already purchased the PCI6254, the SCC-2345, a few feed-through modules, and a couple strain-gauge modules. We have one station set-up fine, it is collecting data perfectly using a simple DAQ assistant.

Problem:

I would like to expand this one program or write multiple subprograms so that each of the 4 stations can be monitored/viewed indepently, triggered independently, all of their data can be stored independently, and separate anaylsis can happen also. We would also eventually like to have a monitor at each of the stations displaying Cp and Cpk information if possible.

Any help with this would be much appreciated even if it is simply a place to start looking. Again I thank you for your time in reading this.

Sincerely,

Dave

[dVaughn]

I almost forgot to mention that there are two signals coming from each station. 1 Force (Strain Gauge or 0-10V) and 1 Distance (0-10V).

[GDE]

Dave,

I was a little confused as to what your looking for.

Are you looking to have one set of hardware (1 PCI-6254 and 1 SCC-2345 setup) on one of your four station, let’s call this station A, and then have your 3 other station (B-D) somehow access the hardware on A? And each machine would do there own thing with the hardware on A. If this is the case, I would highly recommend getting 4 setups for each machine.

Or…

Are you looking to have one test machine, lets call it machine 0, that has the hardware (1 PCI-6254 and 1 SCC-2345 setup) and it collects data from station 1,2,3, and 4. Each of the tests would be independent in analysis and data storage. This sounds more of what you are trying to do, but I want to make sure before going forward. If this is the case, I would also ask do each of the tests for the 4 stations need to run at the same time, or are you looking to have say a user pick which station to test, run the test, do the analysis, store the data, then have the option to start another test on stations 1-4?

If you could clarify which of these setups you are trying to do, I would be glad to offer any advice I can to help you.-GDE

[dVaughn]

GDE,

I apologize for the confusion. The second situation is the situation that we are looking at. We will have 1 test setup that will collect data from stations 1-4. As far as operating at the same time, they will on occasion.

These stations are part of a manufacturing line so therefore there is 1 person running each station. Once the person at station 1 completes his/her operation, they pass that part onto station 2. It is entirely possible for the person at station 1 to begin with the next part at or overlapping the time when the person at station 2 is performing his/her action on the previous part.

I hope that helps clear things up. The approach that I have taken to getting one station going is by duplicating the Cont Acq&Graph Voltage & SW Trigger example and modifying it to add my second channel for station 1. If you think that this is not a good approach please let me know. I was also considering placing a SubVI in the case structure to do any analysis such as SPC graphs, etc. Is this a good idea from a multi-threaded standpoint?

Thanks for your help.

[Dennis_Knutson]

You have a single DAQ card with a single A/D converter on it. You cannot run more than one task simultaneously and independently. That is simply a limitation of the hardware. You could set up a program that samples from station 1, stops, samples from station 2, stops, and so on or you could set up a single DAQ task that continuously samples from all stations, write the information to a queue for example, and then in independent loops, extracts just the data that pertains to a particular station.

[dVaughn]

The queue example sounds like a plan. As long as at the end I get the data from each station that's all I really care about.

Is there a card that has more than one A/D converter on it that you know of and is it worth getting that as opposed to the PCI6254? Or is it just as easy and beneficial to do it programatically?

Also, in each independent loop can I run a SW trigger based on the data in the queue or simply just extract data within a certain Y range?

[Dennis_Knutson]

NI has the S series of boards with 2,4,8 independent A/D's. With the 6254, I don't think you could have independent hardware triggers but you could do it in software like you mention.