Chapter 2 Configuration and Installation
© National Instruments Corporation 2-7 Lab-NB User Manual
Signal Connection Descriptions
Pin Signal Name Description
1-8 ACH<0..7> Analog input channels 0 through 7 (single-ended).
9 AIGND Analog input ground.
10 DAC0 OUT Voltage output signal for analog output channel 0.
11 AOGND Analog output ground.
12 DAC1 OUT Voltage output signal for analog output channel 1.
13 DGND Digital ground.
14–21 PA<0..7> Bidirectional data lines for port A. PA7 is the MSB, PA0 the LSB.
22–29 PB<0..7> Bidirectional data lines for port B. PB7 is the MSB, PB0 the LSB.
30–37 PC<0..7> Bidirectional data lines for port C. PC7 is the MSB, PC0 the LSB.
38 EXTTRIG External control signal to start a timed conversion sequence.
39 EXTUPDATE* External control signal to update DAC outputs.
40 EXTCONV* External control signal to trigger A/D conversions.
41 OUTB0 Counter B0 output.
42 GATB0 Counter B0 gate.
43 OUTB1 Counter B1 output.
44 GATB1 Counter B1 gate.
45 CLKB1 Counter B1 clock.
46 OUTB2 Counter B2 output.
47 GATB2 Counter B2 gate.
48 CLKB2 Counter B2 clock.
49 +5 V +5 V out, 1 A maximum.
50 DGND Digital ground.
Note: Pin 49 is connected to the NuBus +5 V supply via a 1 A fuse. A replacement fuse is available
from Allied Electronics, part number 845-2007, and Littelfuse, part number 251001.
* Indicates that the signal is active low.
The connector pins can be grouped into analog input signal pins, analog output signal pins,
digital I/O signal pins, and timing I/O signal pins. Signal connection guidelines for each of these
groups are included later in this chapter.
Analog Input Signal Connections
Pins 1 through 8 are analog input signal pins for the 12-bit ADC. Pin 9, AIGND, is an analog
common signal. This pin can be used for a general analog power ground tie to the Lab-NB. Pins
1 through 8 are tied to the eight single-ended analog input channels of the input multiplexer
through 4.7-kΩ series resistances. Pin 40 is EXTCONV* and can be used to trigger conversions.
A conversion occurs when this signal makes a high-to-low transition. It can only be used to