Model: PCI‑6703

Part Number: 778316‑01 / 183689G‑02

Brand: National Instruments (NI)

Type: 16-bit, 16-channel static analog voltage output card + 8-channel DIO

Bus: Standard PCI (5 V, half-length card)

Connector: 1 × 68-pin SCSI (female)

Driver: NI‑DAQmx

Status: Out of Production (EOL), recommended replacement: PCIe‑6738

Core Overview

PCI‑6703 is a software-timed (static) analog voltage output card that provides 16 channels of 16-bit voltage output (±10 V) + 8 channels of 5 V TTL/CMOS digital I/O. All channels are multiplexed by a single DAC, each channel has sampling hold (S/H), suitable for slow, high-precision, stable voltage control scenarios such as calibration sources, setpoint control, DAC simulation, relay / valve control.

Main Specifications

Analog Output (AO)

Channels: 16 single-ended voltage outputs

Resolution: 16 bits

Output Range: ±10 V (default)

Accuracy: ±0.001% of full scale

Stability Time: Typical 14.4 ms, Maximum 48.8 ms

Temperature Coefficient: 5 μV/°C (Offset), 1 ppm/°C (Gain)

Update Mode: Software Timing (Static)

Scan Period: 50 μs per channel × 18 channels = 0.9 ms

Digital I/O (DIO)

Channels: 8 bidirectional, 5 V TTL/CMOS

Input: Low ≤ 0.8 V; High ≥ 2.0 V

Output: Low ≤ 0.55 V @ 16 mA; High ≥ 2.4 V @ 16 mA

Power-On State: Input High-Z Power supply

+5 V @ 1.5 A

±12 V @ 70 mA (for analog circuits)

Operating temperature: 0 ~ 55 °C

Features: User-defined power-on state, short-circuit protection, S/H holding accuracy Typical application

Instrument calibration source (voltage reference, sensor calibration)

Industrial process setpoint control (valves, heating, pressure)

Slow and precise voltage output (no high-speed waveform requirements)

Relay / contactor drive, analog load

ATE static testing, DAC simulation, closed-loop control

PCI‑6703 User Manual (Chinese version - simplified operation)

1. Hardware Installation

Power off: Turn off the PC and unplug the power cord.

Insert card: Insert PCI‑6703 into the 5 V PCI slot and tighten the retaining screw.

Wiring:

Use SH68‑68‑D1/E1 shielded cable to connect to the 68-pin SCSI port

AO: AO0–AO15 (±10 V, single-ended)

DIO: D0–D7 (bidirectional 5 V TTL)

Power / Ground: +5 V, ±12 V, GND (connector auxiliary power supply)

2. Driver and Software Installation

Install NI‑DAQmx (required, supports Win7/10/11)

Open NI MAX:

Devices and Interfaces → Find PCI‑6703

Right-click self-check, display "Passed" for normal operation

Development Environment: LabVIEW, C/C++, Python, VB (DAQmx API)

3. Analog Output Configuration (DAQmx)

Mode: Static voltage output (software timing)

Range: Fixed ±10 V

Update: Software write value, hardware S/H maintained

Power-on state: Can be set to 0 V, ±10 V or open circuit

Load: Each channel ≥ 1 kΩ (avoid voltage drop)

Protection: Output short circuit automatically limits current

4. Digital I/O Operations

Direction: Set input/output by byte

Read/write: Static read/write (no handshake)

Power-on: Default input is open circuit, prevent false triggering

5. Key Considerations

Non-high-speed card: No hardware clock, no waveform generation; suitable for slow, stable voltage

Load resistance: ≥ 1 kΩ; otherwise, accuracy decreases

Common ground: Load and card are connected to common ground, reduces noise

Channel crosstalk: Low in slow mode; shielded lines required for high-speed switching

Out of production: New design recommends using PCIe‑6738 (32 channels, 1 MS/s)

6. Common Problems

Output not accurate: Check load ≥ 1 kΩ, common ground, calibration

Channel drift: Preheat for 30 minutes, stable environmental temperature

Cannot find device: Switch to 5 V PCI slot, reinstall DAQmx, refresh MAX