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Maximum throughput

7001, 7002 and Switch Cards
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jvincent
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Country: United States

Maximum throughput

Post by jvincent » September 8th, 2010, 11:56 am

What is the maximum throughput or switching that can be attained with the 7001?

Dale C
Keithley Applications
Keithley Applications
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Re: Maximum throughput

Post by Dale C » September 8th, 2010, 12:06 pm

The maximum throughput on the Model 7001 is

* 130 channels per second using the 7011 card using individual channels
* 125 channels per second using the 7011 card using memory patterns
* 500 channels per second on the 7015 Solid State Relay card using individual channels.
* 450 channels per second on the 7015 Solid State Relay card using memory patterns.

jvarsanik
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Joined: November 7th, 2012, 3:01 pm
Country: United States

Re: Maximum throughput

Post by jvarsanik » November 7th, 2012, 3:12 pm

I have the same question for a 7708. I have 2 7708 cards in a 2700. I want to measure all 80 thermocouples as fast as I can.

Right now, to test, I have 4 thermocouples connected and cycle through them multiple times to get 80 total data points by setting "SAMP:COUN 80". However, when I do this, it takes around 8 seconds to get through all 80. I expected it to be faster.

I appreciate any input.

Thanks,

Jon

Dale C
Keithley Applications
Keithley Applications
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Re: Maximum throughput

Post by Dale C » November 8th, 2012, 5:51 am

The specs for scanning TCs with a 2700 and 7708 state about 50 switch reads per second. So at the maximum rate I would expect this to scan the 80 channels in about 1.6 seconds.
There are a few parameters that affect the speed.
1. Integration rate (NPLC). Set this to 0.01 :SENSE:TEMP:NPLC 0.01, (@101:104)
2. Filter. Disable the filter. :SENSE:TEMP:AVER:STAT OFF, (@101:104)
3. Autozero. Disable AutoZero. :SYSTEM:AZERO:STAT OFF
4. Trigger delay. Set trigger delay to Zero. :TRIGGER:DELAY 0.0
5. Display. Disable the display. :DISPLAY:ENABLE OFF

These commands should help speed it up.

jvarsanik
Posts: 4
Joined: November 7th, 2012, 3:01 pm
Country: United States

Re: Maximum throughput

Post by jvarsanik » November 8th, 2012, 1:29 pm

Thanks Dale!

Those commands definitely sped it up significantly. However, I do not see where this spec came from. Looking in the datasheets, I see that the 770 has an actuation time of "<3 ms" and the 2700 can scan at 180 samples per second. Where does the 50 reads per second come in?

Thanks again.

Dale C
Keithley Applications
Keithley Applications
Posts: 2847
Joined: June 10th, 2010, 6:22 am
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Re: Maximum throughput

Post by Dale C » November 12th, 2012, 6:12 am

For this spec look at the specs on this link. Look at page 1 lower right hand corner.
http://www.keithley.com/support/data?asset=50256

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