II. Model Interpretation

PXI: Standard 3U single slot, compatible with PXI/PXIe mixed slots, supports PXI trigger bus and RTSI real-time synchronization bus.

7344: 73xx motion control series, 4 represents 4 axes, 4 represents enhanced (Enhanced), compared to 7340, it improves control cycle, interpolation accuracy and program execution capability.

Positioning: 4-axis high-performance servo/stepper enhanced motion control card, suitable for complex trajectories, high-speed linkage and nanosecond-level synchronization scenarios.

III. Technical Parameters (25℃)

1. Motion Control Core

Control Axis Number: 4 axes independent/synchronous, servo (brushed/brushless), stepper motor compatible.

Control Cycle: 62 μs/axis (improved compared to 7340), total 4-axis cycle 250 μs.

Position Range: ±2³¹ counts (servo)/±2³¹ steps (stepper).

Speed: servo 20 M counts/second; stepper 4 M steps/second.

Acceleration: servo 244~512 M counts/second²; stepper 2.44~512 M steps/second².

Control Modes: PID/PIVff/double loop control/S-curve, supports electronic gearing, 3D straight line/arc interpolation.

2. Analog I/O

Analog Output (AO): 4 channels ±10 V, 16 bits, servo command output.

Analog Input (AI): 8 channels ±10 V, 16 bits, sensor/feedback acquisition.

3. Encoder and Feedback

Encoder Interface: 4 channels A/B/Z phases, up to 4 MHz, supports incremental encoders.

Feedback Type: encoder, analog quantity, pulse command, supports double-loop feedback.

4. Digital I/O

Channels: 32 TTL, bidirectional configurable, 16 input/16 output each.

Level: high ≥ 2.4 V, low ≤ 0.4 V, maximum pull/hold current 8 mA.

5. Physical and Environmental

Connector: 2×68-pin VHDCI (motion I/O + digital I/O).

Power Supply: PXI backplane + 5 V/+12 V/-12 V, power consumption approximately 18 W.

Operating Temperature: 0 ℃ ~ 55 ℃.

Storage Temperature: -20 ℃ ~ 70 ℃.

IV. Interface and Communication Configuration

1. Hardware Interface

Motion I/O (68-pin): 4 channels encoders, 4 channels AO, 8 channels AI, limit/origin, break point input.

Digital I/O (68-pin): 32 TTL, used for triggering, interlock, status monitoring.

Backplane: PXI trigger bus (8 channels), RTSI bus, multi-module synchronization accuracy **<100 ns**.

2. Software and Drivers

Driver: NI-Motion, supports complex interpolation, electronic gearing, fly saw, contour control.

Development Environment: LabVIEW, C/C++, Python, TestStand, supports real-time control.

Functions: On-board multi-task (10 programs), hardware breakpoints (200 ns), watchdog (63 ms), fault-safe shutdown.

V. Core Functions

Enhanced 4-axis closed-loop control, 62 μs high-speed update

Each axis 62 μs PID update (better than 7340's 62.5 μs), supports servo/stepper mixed control; RTSI bus synchronization, multi-axis timing jitter **<100 ns**.

On-board real-time multi-task and complex trajectory interpolation Dual processors + real-time OS, capable of running 10 motion programs simultaneously; natively supports 3D linear/arc interpolation, contour control, and electronic gearing, without occupying the host CPU.

Rich I/O integration, integrated control

4 channels of 16-bit AO, 8 channels of 16-bit AI, 32 channels of TTL I/O, 4 channels of encoders, directly connect to motors, sensors, limit switches, simplifying the system architecture.

Advanced control algorithms and safety protection

PID + feedforward control, S-curve acceleration/deceleration smoothness; hardware limit, software limit, watchdog, short circuit protection, automatic safe shutdown in case of faults.

System-level synchronization and integration

Share the clock and trigger with PXI data acquisition, vision, and FPGA modules to build a unified time reference, suitable for complex automation system integration.

Six. Application scenarios

Precision processing and manufacturing

Laser cutting, CNC precise positioning, semiconductor wafer handling, PCB drilling, complex trajectories and micrometer-level positioning requirements.

Automation testing and verification

Multi-axis motion platform testing, sensor calibration, product lifespan testing, robot joint performance verification, high-speed dynamic response scenarios.

High-speed precise positioning system

Electronic manufacturing assembly machines, optical platforms, biological 3D printing, high-speed sorting machines, high dynamic response and complex motion trajectory requirements.

Servo/stepper motor control

Industrial robots, CNC machines, packaging machinery, textile equipment, multi-axis synchronous and联动 control.

Research and laboratory automation

Optical instruments, precision measurement equipment, automated experimental platforms, nanosecond-level synchronization and high-precision motion control.

Seven. Installation and Maintenance Instructions

1. Installation and Power On

Disconnect power， insert into any slot of the PXI chassis， tighten screws and reliably ground； before powering on， check that the 68-pin cable has no short circuit / false connection to avoid damaging the I/O channels. Keep the chassis ventilated during operation， with an ambient temperature of ≤55℃ to avoid temperature accumulation affecting control accuracy.

2. Wiring and Operation

Cables： Use shielded 68-pin VHDCI cables， separate analog signals， encoder signals， and digital signals for wiring to reduce crosstalk； encoder cable length ≤10 m to avoid signal attenuation.

Configuration： Set the axis type (servo/stepper)， control mode， limit parameters， trajectory data in the software； for the first run， perform no-load debugging first， confirm normal motion before connecting the load.

Synchronization： When synchronizing multiple cards， use PXI_TRIG or RTSI signals to ensure consistent timing； the hardware breakpoint is used for precise triggering of external events.

3. Daily Maintenance

Regularly clean the 68-pin connectors， check the integrity of the cable shielding layer， add a dust cap for long-term storage to prevent oxidation and dust from affecting contact reliability.

Calibration： Suggested once a year， use the NI-Motion calibration tool， calibrate the accuracy of analog I/O， encoder zero points， and limit trigger values.

Driver update： Regularly update the NI-Motion driver and firmware to fix compatibility issues and optimize motion control stability.