Hi, 4351 applicable to measure ac voltage?

[genka]

Hi, this time we want to function this card as oscilloscope on PC. but the problem is output welding card is 220-240 ACV and the clock is 5 DCV. Is it applicable for 4351 PCI card to measure ac voltage? If no, any suggestions for what card series should i use(must have more than 2 channel Analog IO and several Digital IO port)?

Thank you,

Best regards,

Irwan

soh.irwan@gmail.com

[gwd]

This is a data logger card, designed for very high resolution measurements at low speed. Maximum sampling rate is 60 samples/ sec. So you could measure AC up to, maybe, 15 Hz with four samples/ cycle. Probably not what you want.

Remainder of question doesn't make sense to me.

[johnsold]

Very few, if any, standard data acquisition devices will measure 240 VAC directly. The magnitude of the voltage and isolation for safety are both issues. At these voltage levels safety of personnel and equipment must be carefully considered.

If bandwidth is not an issue, a small filament transformer (240 V to 6 V) would isolate the high voltage and reduce it to a usable level. Even with this, you might want to provide some clamping devices to protect the DAQ instrument from transients. Calibration will be required, especially if you choose a commodity transformer rather than an instrumentation transformer, which should have a calibration certificate.

Lynn

[Brian F.]

Hello Irwan.

Both gwd and Lynn are correct in their statements.  The 4351 is designed to take very accurate measurements, which because of their resolution, limits their acquisition rate.  The maximum input voltage on the 4351 is 15 V so inputting 220 V AC would damage the card.  The highest input that can be input to one of our DAQ cards is 42 Volts which are our 6110, 6111, 6115, and 6120 cards which are members of our S series product line.  We do offer DMM's, such as the PCI-4070, that can handle 300 Volts of input.  The 4070 can also aquire at a speed of 1.8 MS/s isolated if you wish to do a high-voltage waveform acquisition.  This is your best bet because of the high voltage, AC measurements that you wish to take.  More information on the PCI-4070 is available at:

NI PCI-4070
https://www.ni.com/en-us/shop/model/pci-4070.html

Good luck and if you have any other questions on the 4070, we would be happy to answer them!

Brian F
Applications Engineer
National Instruments

[genka]

Hi all, thanks for your quick replying.

due to the high cost,   we already have scope Tektronix(TDS 220), I think we better use the scope and just take data from gpib port.

Best regards,

irwan