Reading a streamed channel

[Jimmy1125]

Hi

Could you tell me how to read a streamed channel with timing of 0.0? I use the channel for a sequence to find Bottom dead center. I don’t want to read it while streaming because I don’t want the data to add to channel history. I’m plotting the streamed data and afterwards I need to read this channel to return to Bottom. 

Thanks

[AzeoTech]

Sure, just do:

read(myChannel)

 

[Jimmy1125]

Won’t this read the channel once? I need to read it continuously until motor reaches bottom dead center. 

[Jimmy1125]

Hello

Disregard my last question. I went back and reread the chapter and got it working. 

The only thing wrong now is the sequence won’t end on it’s own. Am I missing something? Shouldn’t it end itself when completed?

Thanks

[AzeoTech]

I don't know what you have.  Can you post your script?

[Jimmy1125]

Hi

Thanks for responding. I had a while(1), read(channel) with a if() followed by another while(). Once I removed the first while() everything worked. 

Now I need some help on counting. I saw the post on counteroffset. I’d like to read 125 counts but I’m having trouble figuring it out. Do I  put something in the RawCounts channel event? Or do some type of sequence?

[AzeoTech]

What do you mean by counting?  Do you want to read 125 times then stop?  I'm unsure what you want to do.

[Jimmy1125]

Sorry

I’d like to stat my stream and read for 125 counts then stop stream. Or possibly just log the data corresponding to those 125 counts. 

[AzeoTech]

Starting and stopping the stream like that is impossible because DAQFactory only sees the data in blocks.  You can log that data, however, using an export set.  Just clear the history of the channel before starting the stream (myChannel.clearHistory()), then start the stream.  Once you stop the stream you can log the first 125 values using the expression:

myChannel[numrows(myChannel)-126, numrows(myChannel)-1]

in the export set.