Chapter 3 Signal ConnectionsDAQCard-1200 User Manual 3-4 © National Instruments CorporationThe connector pins are grouped into analog input signal pins, analog outputsignal pins, digital I/O signal pins, timing I/O signal pins, and powerconnections. Signal connection guidelines for each of these groups aredescribed in the following sections.Analog Input Signal ConnectionsPins 1 through 8 are analog input signal pins for the 12-bit ADC. Pin 9,AISENSE/AIGND, is an analog common signal. You can use this pin as asignal ground connection to the DAQCard-1200 in RSE mode, or as areturn path in NRSE mode. Pin 11, AGND, is the bias current return pointfor differential measurements. Pins 1 through 8 are tied, through 4.7 kΩseries resistances, to the eight single-ended analog input channels of theinput multiplexer. Pins 2, 4, 6, and 8 are also tied to an input multiplexerfor DIFF mode.The signal ranges for inputs ACH<0..7> at all possible gains are shown inTable 3-1. Exceeding the input signal range will not damage the inputcircuitry as long as the maximum input voltage rating of ±35 V powered onand ±25 V powered off is not exceeded. The DAQCard-1200 is guaranteedto withstand inputs up to the maximum input voltage rating.Warning Exceeding the input signal range distorts input signals. Exceeding the maximuminput voltage rating may damage the DAQCard-1200 and the computer. NationalInstruments is NOT liable for any damages resulting from such signal connections.45 CLKB1 DI DGND Clock B1—External control clock signal for counter B1.46 OUTB2 DO DGND Counter B2—Voltage output signal of counter B2.47 GATB2 DI DGND Gate B2—External control signal for gating counter B2.48 CLKB2 DI DGND Clock B2—External control clock signal for counter B2.49 +5 V DO DGND +5 Volts—Fused for up to 1 A of +5 V supply, but limitcurrent to 250 mA.50 DGND N/A N/A Digital Ground—Voltage ground reference for the digitalsignals and the +5 V supply.*Indicates that the signal is active low.AI = Analog Input DI = Digital Input DIO = Digital Input/OutputAO = Analog Output DO = Digital Output N/A = Not ApplicablePins Signal Name Direction Reference Description
