Using 1102 & 1308 cards for different input types

[Fox farmer]

If I am using 1102 and 1308 cards to receive both voltage and current signals, can I remove the resistors from the 1308 on the channels I do not want voltage inputs?  I guess another way of asking is, is it possible to still send current signals "through" the 1308 straight to the 1102 so that I can use only one 1102 card for my application?

[enderWiggin10]

Good morning Fox farmer,

There are resistors built into the board for current input because the card will actually measure the voltage drop across the 249 Ohm precision resistor according to the manual. We can then calculate the current using Ohm's Law by dividing the voltage drop by 249 Ohms.  I went ahead and added an SCXI-1000 chassis with a 1102 in slot1 with a 1308 connector block.  I was successful in measuring both voltage and current in the same task.  With that said, it should not be necessary to remove the resistors to measure current, and it is not recommended.

Best,

[Fox farmer]

Adam,

Thanks for the reply.  The 1308 block will likely work great for my application when measuring current.  However, only 18 of the inputs I'm receiving on this card will be used for current measurements (actually 4 for current transducers, and 10 for mv signals from psi transducers). 

The other 14 (channels) will be used to measure voltage input from thermocouples (10x) and voltage inputs from voltage transducers (4x).  On these channels used to measure voltage I WILL need to remove the resisters, correct?

 Thanks!

Jim

[enderWiggin10 · Accepted solution]

Good morning Jim,

Thank you for the clarification, I misunderstood the initial inquiry.  When referencing the manual for the SCXI-1308, it can be read on page 2 that you can measure both current and voltage.  In order to measure voltage, you must remove the resistor in the current-loop, and it later identifies the resistors and their respective channels on the following page, 3.  With that said, removing the resistors will not be an issue.

Best,