©
National Instruments Corporation
E-1
E
Current-Loop Receivers
Notes
NI recommends that you use the NI-1308 with socketed shunt resistors.
You must remove soldered resistors for calibration.
The SCXI-1102/B/C modules have pads for transforming individual
channels to current-to-voltage converters. NI offers an SCXI
process-current pack of four 249
Ω
, 0.1%, 5 ppm, 1/4 W resistors. The
reference designators for the current loop resistors have the format: for
input channel
x
, the resistor is RCL
x
. For example, the resistor for channel
28 is RCL28.
Caution
Before installing the resistors in the module, make sure that there are no signals
connected to the module front connector.
Before installing the module in the SCXI chassis, you must install the
resistors by completing the following steps:
1.
Ground yourself with a grounding strap or with a ground connected to
the SCXI chassis.
Note
Properly grounding yourself prevents damage to the SCXI module from electrostatic
discharge.
2.
Remove the grounding screw of the top cover.
3.
Snap out the top cover of the shield by placing a screwdriver in the
groove at the bottom of the module and pushing down.
4.
Remove the rear panel by unscrewing the two remaining screws.
5.
Slide the module out of its enclosure.
