A possible PXI-1052 and SCXI-1520 mismatch ?

[Damill]

Please help us,

We have run into problem with our PXI-1052 chassi. It has an embedded controller PXI-8186, four SCXI-1142, one SCXI-1520, one SCXI-1102C and one SCXI-1163R. When sampling 48 channels at 1000 Hz, the signal connected to SCXI-1142, ch0,  in slot 3 gets corrupt with a strong offset error. 

Reducing the number of channels or sampling rate does not affect the problem but as soon as we disconnect sampling of any channel on the SCXI-1520, then the problem is gone. In the channel list,  the SCXI-1520 is scanned immediately before the SCXI- that has a problem. wE wE This sound to us as a hardware problem with impendance problems on the analog bus  

Regards,

Dan Larsson

Damill Av Sweden 

[devchander]

SCXI 1520 should be placed in the first SCXI slot while using it in a multi SCXI module setup.

Just put SCXI 1520 in first SCXI slot and put SCXI 1140 in slots after SCXI 1520 ( this order can be interchanged since both these modules are SSH enabled)

But always insert  1102 and1163 modules after these two modules( in the last, since both do not have SSH enabling)

this should solve your problem

[Damill]

Thank you for the advise,

We have not tested it but we got the advise to slow down the AI conversion rate manually with a property node and that fixed the problem!

DAQmx automatically sets the conversion rate to max (to match 333 ks/s) when it finds a 1520 card and that might leed to crosstalk between some other channels which was exactly what we got. We dropped AI conversion rate to 100 kHz in our 48 KS/s environment

/Dan and Roger, Damill AB