Voltage to Temperature convertion problem _ 1560 Hart Scientific Black Stack

[Sakib001]

Hi All,

I am trying to acquire temperature data from a "Hart Scientific 1560 Black Stack Temperature Readout" using analog voltage signals. I have a PCI - 6023E card installed in my computer and I have 64 pin CB-68LP terminal block as the accessory. I have connected the analog outputs from the Black Stack Thermometer to the terminal block in defferential configuration. I have used NI-DAQmx to write the code and the Callender-van Dusen equation coefficients toconvert the voltage readings to temperature readings. But, the temperature values i am getting are very very abnormal. Please help me with this ...

I have some snapshots of the code in the attachment.

[RavensFan]

More info please.

What does the data look like?  What are the temperatures you are calculating that are "very very abnormal"?

What does the raw voltage data look like?  Attach a waveform chart to that, run it and show us.  Does the general appearance look right, or could it be electrically noisy?

What raw voltage values do you expect to get?

A screenshot doesn't help because 1/2 the really important information is hidden inside the DAQ assistant.  How that is configured could be a huge difference between success and failure.

[Dennis_Knutson]

It also seems the device has an RS-232 port that you can use for direct temperature readings.

[Sakib001]

Hi RavensFan,

Please find your answers as below:

1. The temperature is displayed around 19 - 20℃ in the temperature readout; but when I run the code in LabView, it is showing around 9200℃; which is quite abnormal

2. Please find the raw voltage and the converted temperature data in waveform charts in the attached pictures. The general appearance of the raw voltage is quite okay to me.

3. According to the manual of the FLuke 1560 temperature readout, "The analog output sources a DC signal (±1.25 VDC) corresponding to the value of a measurement.". But, as you see in the waveform chart, I am getting voltage values in the range of -1.18V to -1.34V. I don't know why it is behaving like this ...

I have also attached a snapshot of the configuration of the DAQ assistant and also the code.

Hope these help you in understanding the situation ...

[Sakib001]

Hi Dennis Knutson,

Yeah, it has one serial and also one GPIB port; but I don't have any NI PCIe-Serial or PCIe-GPIB cards. The only one I have is the PCI-6023E that only runs with analog signals. Is there any other way that I could get the data out of the serial/GPIB ports and get them plotted in LabView? Please help ...

[RavensFan]

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@Sakib001 wrote:

Hi RavensFan,

Please find your answers as below:

1. The temperature is displayed around 19 - 20℃ in the temperature readout; but when I run the code in LabView, it is showing around 9200℃; which is quite abnormal

2. Please find the raw voltage and the converted temperature data in waveform charts in the attached pictures. The general appearance of the raw voltage is quite okay to me.

3. According to the manual of the FLuke 1560 temperature readout, "The analog output sources a DC signal (±1.25 VDC) corresponding to the value of a measurement.". But, as you see in the waveform chart, I am getting voltage values in the range of -1.18V to -1.34V. I don't know why it is behaving like this ...

I have also attached a snapshot of the configuration of the DAQ assistant and also the code.

Hope these help you in understanding the situation ...

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What voltage do you expect to get for the 19-20°?

What voltage do you read off the device if it is not connect to the DAQ card, but you just read it with a multimeter?

[Dennis_Knutson]

A usb-rs232 converter is very cheap.

[Dennis_Knutson]

p.s. Your first post says you connected as differential but the DAQ Assistant shows you are running as single ended. How have you physically connected the wires?

[Sakib001]

For 19 - 20 degree C, the voltage is should be around 0.107 - 0.108 Volts; but the code is showing voltage around 0.014 - 0.015 volts ...

I used the multimeter;

- when connected to the DAQ cad, it is showing the same value as displayed by the LabView code,

- when not connected to the DAQ card, it is showing values around 1.25 volts ...

Don't know what to do ...

Please help

[Sakib001]

I think first I tried with the differential connection; but I think that was not the right was to approach. Now i am using the RSE connection. I have attached a snapshot of the physical connection of the wores out of the device. Please have a look and suggest whether I am wrong with this ...