labview and serial comms with dmm

[Dennis_Knutson]

No, it should be after the last write and before the read. In your example, just add another sequence at the end and put a wait (ms) in there. Start with a wait of 100 msec and see if that works.

[toffee]

i put in a wait (ms) block in a new frame in the write block.  i just keeps switching (the dmm), clicking and nothing happens. looks like i did this wrong. or haveent use the ms correctly. i joined one end to the sequence frame and the other i put in a numeric value (100 in this case)

[Dennis_Knutson]

It should look something like the attached. I also modified the sequence structure to show you the correct way to pass data from one sequence to the next.

[toffee]

hey dennis

still no luck, every 100ms the dmm 'clicks' and you get no reading , nothing! when it runs in debug mode it does work. weird.

when i deleted the time delay it worked as per before, jumping up and down .so looks like back to the drawing board!

[Dennis_Knutson]

You might try increasing the delay. Running a VI in execution highlight mode really slows down a VI and if it works there, usually indicates that a there is not enough delay. Try something very high like a couple of seconds. If it you find a setting that works, you can start backing off until it stops reading.

[toffee]

ok, i seem to have some progress, i changed the delay to 7 seconds, and it worked as required, no jumping and it reacted to changes in the volts.

but when i exited the program and ran it again, it didnt work? i was grabbing a screen shot of the graph, but due to some settings on this computer i couldnt save it. so anyway, it was working correctly for a period of time, say a minute, then it justs stops reading and stays at zero volts. if i kept it running it perhaps would have picked up again and but theres still something out. do i need a wait before the read block?

[toffee]

hey dennis

i have solved the earlier issue, it was to due with the write command inside the loop, i moved it outside the loop and now it doesnt 'jump', now i got a problem , another one! i get nothing coming out of the string converter block, i get some weird square blocks before the reading, say [][][][][]4.9v   etc...... then coming into the graph i get nothing, so it seems these [][][][] blocks are a problem, any idea whats going on?

thanks

eric

[toffee]

ok, you can ignore all that! i loaded the program again, works ok, looks like gremlins!

thanks for the help, i got 3 different graphs, alot of mess. how can i get current and volts on 1`graph? i have power on a seperate one,

regards

[Seamus_C]

Hi Toffee,

You can use the bundle function, or merge signals function.  A better way to do this is to use the mixed signals graph.  If you want to post your current vi and I will be able see exactly what you mean. 

Hope this helps,

Seamus