Self calibration, which lines must be disconnected

[Lunarfur]

Hallo,

in einer Anwendung wird die Messkarte PCI-6225 mit einer selbst-entwickelten Elektronik über SHC68-68-EPM verbunden. Da das Gerät in einer Umgebung mit Temperaturschwankungen > 1°C verwendet wird, ist eine häufige Selbstkalbrierung notwendig.

Die Elektronik lässt sich komplett abschalten (mechanische Trennung der Versorgungsspannung), jedoch tritt bei der Selbstkalibrierung ein Fehler auf, mit dem Hinweis die externen Signale zu entfernen. Eine wiederholte Trennung des VHDCI Steckers führt jedoch zum defekt des Steckers durch verbiegung und irgendwann auch abgebrochenen Pins. Daher meine Frage, welche Signale tatsächlich mechanisch entkoppelt sein müssen, damit eine Selbstkalibrierung durchgeführt werden kann?

Vielen Dank

DI Andreas H.

Hello,

I'm using a PCI-6225 which is connected via SHC68-68-EPM to a custom-made electronic. When using the self calibration procedure, I get an error telling me to disconnect all external signals. Switching off the connected electronic still produces this error.

As the temperature in my application environment change with more than 1°C easiliy within a day the need for self-caibration occurs very often, so disconnecting the VHDCI will lead to malfunction, because of bended or broken pins.

So my question is: which signals need to be mechanically disconnected to enable self calibration?

Thank you

Dipl.-Ing. Andreas H.

[Lewis_G]

Hi,

I believe that most legacy hardware may require you to disconnect signals, but M and X Series boards do not.  There are 3 tiers of multiplexers before the ADC, the external signals will be cut off at the first one when the Self-Cal routine is initiated.

I just calibrated my NI PCI-6251 (M series) while external signals were connected and it passed self calibration.

Could you give me the error code you are receiving or upload of screenshot of the error?

Kind Regards

[Lunarfur]

Error is:

Self-calibration failed.
Disconnect the device from external signals, as they might introduce noise. Externally calibrate the device to recalibrate the onboard voltage reference that ist used for self-calibration.

Status Code: -200545

probably the only way is a multipolar relais to galavanically disconnect all signals?

Thank you for investigating.

[Lewis_G]

Hi Lunarfur,

After looking into the error you’re receiving I feel the best course of action would be to call your local National Instruments branch.  They will be able to support the issues you are having with your hardware.

It could be a case of performing an external calibration on the device or starting a return merchandise authorization (RMA) if the device is faulty.

Kind Regards