National Instruments NI 9945, NI 9944 User Manual

USER GUIDE

NI 9944/9945 Quarter Bridge Completion Accessory

This document describes the features of the National Instruments 9944 and
9945 Quarter Bridge Completion Accessories, referred to inclusively in
this document as the NI 9944/9945. You can use the NI 9944/9945 to add
a quarter bridge to the NI 9237 module. Refer to the NI 9237 Operating
Instructions for more information about the NI 9237.

NATIONAL
INSTRUMENTS

Figure 1. NI 9944/9945 Quarter Bridge Completion Accessory

What You Need to Get Started

To use the NI 9944/9945, you will need the following:

❑ Plastic tie strap for strain relief wrapped around the two front holes,

as shown in Figure 3

❑ M4x20 screw, or other hardware that fits in the 8.89 mm (0.350 in.)

outer clearance hole and 4.57 mm (0.180 in.) inner clearance hole,
as shown in Figure 3

NI 9944/9945 Dimensions

The NI 9944/9945 has outer dimensions of 66 × 21.6 × 22.96 mm
(2.6 × 0.85 × 0.90 in.), as shown in Figures 2 and 3.

Specifications

0 EX+

1 IN+

2 QTR

66 mm (2.6 in.)

Figure 2. NI 9944/9945 Dimensions

Holes for
Tie Strap

Figure 3. NI 9944/9945 Dimensions and Hole Clearance

3 Shield

Ø 8.89 mm (0.350 in.)

Ø 4.57 mm (0.180 in.)

21.6 mm
(0.85 in.)

22.86 mm
(0.90 in.)

The following specifications are typical for the range – 40 to 70 °C, unless
otherwise noted.

Weight ....................................................32 g (1.1 oz)

Operating temperature ............................–40 to 70 °C

Resistor value

NI 9944............................................120 Ω

NI 9945............................................350 Ω

Resistance drift

NI 9944............................................0.012 Ω/°C

NI 9945............................................0.035 Ω/°C

Resistor tolerance (at 25 °C)...................0.1% max

Resistor power ........................................0.25 W max

NI 9944/9945 Accessory User Guide 2 ni.com