Is an isolation recommanded between analog measure and an SCXI module?

[Sadok]

Hello,

We are using an SCXI module to acquire AC and DC voltage measerement (range: some mV to 400 Vac).

Do you recommend to put a stage of relay to garantee an isolation between the product and the instrument for security?

the SCXI  include:

SCXI-1000 Chassis

1125

SCXI-1349

1104

1102

Connected to the  PC through PCI-6251

Please I need quick response

thanks

[Dennis_Knutson]

You will get a quicker response if you post to the correct board. This is for a product called Measure - an obsolete add-on for Excel. Post to the multifunction DAQ board.

[Jim_S]

Hello Sadok,

Each of these SCXI modules have different voltages that would cause the module to break. I have included some of the important parameters that you will need to consider. The SCXI 1125 has 300 Vrms working isolation per channel but the SCXI 1104 and SCXI 1102 do not provide this type of isolation. The SCXI 1104 should be within ±42 VACpeak, ±60 VDC of CGND on each input and this can be found in the manual of the device. For the SCXI 1102 the input damage level is when the voltage is ±42 VDC or higher when it is powered on and ±27 VDC when it is powered off.

If you think that the voltages might reach this level, I would consider placing relays in there place as extra isolation. I hope this information helps you and if you have any more questions, feel free to post.