How do I set the NPLC on a Agilent 34970A then keep it set when I do a Temp measurement on the channels

[RTSLVU]

I don't believe the NLPC has any effect on temperature measurements. 

There is a "channel delay" setting that you might want to look into.

Channel delay
You can control the pace of a scan sweep by inserting a delay between multiplexer
channels in the scan list (useful for high-impedance or high-capacitance circuits).
The delay is inserted between the relay closure and the actual measurement on
the channel. The programmed channel delay overrides the default channel delay
that the instrument automatically adds to each channel.

– You can set the channel delay to any value between 0 seconds and 60
seconds, with 1 ms resolution. You can select a different delay for each
channel. The default channel delay is automatic; the instrument determines
the delay based on function, range, integration time, and AC filter setting (see
“Automatic Channel Delays” on the next page).

Automatic channel delays
If you do not specify a channel delay, the instrument selects a delay for you. The
delay is determined by function, range, integration time, and AC filter setting as
shown below.

Table 4-1 DC Voltage, Thermocouple, DC Current (for all ranges)
Integration time Channel delay
PLC >1      2.0 ms
PLC ≤ 1    1.0 ms

[Arda____]

When I used the 34970 library in this way, I was able to take measurements in 0.8s and did not make any adjustments.:D

I can't understand why

[GerdW]

Hi Arda,

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@Arda____ wrote:

I can't understand why

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What exactly don't you understand?

[Arda____]

when ı use the other Daq library(34970) work faster then DAQ970A's library. 34970's library works fine (measure fast)

[GerdW]

Hi Arda,

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@Arda____ wrote:

when ı use the other Daq library(34970) work faster then DAQ970A's library. 34970's library works fine (measure fast)

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Then it does something differently under the hood…

As those device drivers (most often) are free VIs you can look for yourself how the device is configured in those device drivers!

[RTSLVU]

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@Arda____ wrote:

when ı use the other Daq library(34970) work faster then DAQ970A's library. 34970's library works fine (measure fast)

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The DAQ97xA drivers are an IVI type driver while the 3497xA drivers are just SCPI commands.

I don't know why the IVI driver is slower, but there's nothing you can do about it because the IVI drivers use a DLL instead of SCPI commands.

But the VI you are using is part of the "EZ" Vi set, here's how the EZ VI works when you send a command to measure a thermistor.

1. It configures the instrument to measure the thermistor(s) and return the value in the temperature scale you desire
2. It takes the measurement(s)
3. It returns the measurement(s) 
4. It clears the channel configuration that was previously set

While this may be fast enough for your application, it is not as fast as the instrument can operate. 

Using the main VI set and configuring a scan list the instrument operates like this.

1. You configure all channels and measurements at the same time you initialize the instrument

When you trigger a scan to take a measurement the instrument

1. It takes all measurements previously configured
2. It returns the measurements

Not only is this faster  but it had the added advantage of being able to press the "Mon" button on the instrument and the current value will be displayed on the screen. The instrument will not do this using the EZ VI set because the channel configuration is cleared after each individual measurement is taken.

[NIquist]

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@Arda____ wrote:

when ı use the other Daq library(34970) work faster then DAQ970A's library. 34970's library works fine (measure fast)

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Just to verify... You DID change your original DAQ970A code to set the NPLC to 0.02 right???

Your posted code shows the NPLC at 200 which takes 3300mSec.  Then you limit the time to 2000mSec with the MaxTime parameter in Measure Thermistor.vi.  You never told us what the results were for any of this, so we can only try to guess until you provide detailed info of your issue.

Also note that in your code DAQ970A above, you RESET the instrument which means all parameters are at known defaults.  In your later 34970A version you run a read in a loop without initializing anything, which means that all parameters are in an unknown state.  This makes it impossible to compare the results of the two codes since you may have set things through the front panel we don't know about.

[Arda____]

Yes, I set the NPLC 0.02 and ı try with 0.02. Thank you

[Arda____]

Hi RTSLVU,

Its so helpful thank you so much