National Instruments SCXI-1303 Installation manual - Changing Resistor Networks

SCXI-1303 Installation Guide

2

©

 National Instruments Corporation

❑

SCXI chassis

❑

SCXI-1102/B/C or SCXI-1100 module

❑

One package of four 10 M

Ω

 resistor networks

❑

No. 1 and No. 2 Phillips-head screwdrivers

❑

1

/

10

 in. and 

1

/

4

 in. flathead screwdrivers

❑

Long-nose pliers

Changing Resistor Networks

Use long-nose pliers to remove or replace the resistor networks in the 

sockets; be careful not to damage the network package. Make sure pin 1 

of each network is in the correct position in the socket. Refer to Figure 4 to 

locate pin 1 for each resistor network socket.

Each resistor network is labeled with descriptive numbers on the left front 

side, and pin 1 is located directly beneath the darkened symbol within these 

numbers. The 10

 Ω

 resistor network is labeled 100 (10 

×

 10

0 

Ω

); the 10 M

Ω

resistor network is labeled 106 (10 

×

 10

6

Ω

). Figure 1 shows examples of 

these resistors.

Figure 1.  

Resistor Networks

Open Thermocouple Detection

The SCXI-1303 circuitry helps you detect an open thermocouple. To detect 

whether any thermocouple is open, check whether the corresponding SCXI 

module channel is saturated. The SCXI-1303 has pullup and bias resistors 

that saturate the channel by applying +5 V at the input of the open channel. 

Notice that this will result in saturation to either of the positive or negative 

rails.

SCXI-1102/B/C Module

You can replace the 10 

Ω

 bias resistor networks (factory shipping 

configuration) in the SCXI-1303 with the 10 M

Ω

 resistor networks 

supplied in the kit. With the 10 M

Ω

 resistor networks, it does not matter 

Mfr. code

10x-1-100

Pin 1

Mfr. code

10x-1-106

Pin 1

a. 10 

Ω

 Resistor Network

b. 10 M

Ω

 Resistor Network