ADLINK DAQ-2000 Synchronous Sampling and Acquisition Card Selection Guide



ADLINK DAQ-2000 Series Synchronous Sampling Multifunctional Data Acquisition Card Selection and Application Guide

In demanding applications such as excitation response testing, multi-channel sensor signal synchronization acquisition, and vibration and acoustic analysis, phase consistency between channels is crucial. Traditional multiplex scanning ADCs introduce time offset due to channel switching, which cannot meet the requirements of high-precision time-domain or frequency-domain analysis. The ADLINK DAQ-2000 series is a synchronous sampling multifunctional DAQ card designed specifically for such scenarios, providing 4-channel differential analog inputs, each channel equipped with an independent ADC, achieving true simultaneous sampling, with a maximum sampling rate of 2 MS/s (14 bits) or 800 kS/s (16 bits). Combined with 2-channel 12 bit analog output, 24 channel digital I/O, 2-channel 16 bit timer/counter, as well as flexible analog/digital triggering and SSI system synchronization bus, this series of products has become an ideal platform for multi-channel stimulation/response testing, audio analysis, radar signal acquisition and other applications. This article will provide engineers with complete technical references from the aspects of architecture characteristics, model selection, analog input/output specifications, synchronous expansion, software development, and deployment points.

Product Family and Selection Comparison

The DAQ-2000 series includes four models, with the core difference being the sampling rate and resolution, to meet different precision and speed requirements:

Model resolution, highest sampling rate (per channel), applicable scenarios

DAQ-2010 14 bit 2 MS/s high-speed transient signal acquisition (such as shock, explosion, radar pulse)

DAQ-2016 16 bit 800 kS/s high-precision audio and vibration analysis, balancing speed and dynamic range

DAQ-2005 16 bit 500 kS/s universal vibration, strain, and temperature (thermocouple) measurement

DAQ-2006 16 bit 250 kS/s slow process monitoring, such as pressure, flow, and voltage trend recording

All models offer:

4-channel differential input, with an input range of ± 1.25V to ± 10V (bipolar) or 0~1.25V to 0~10V (unipolar), and supports programmable gains of x 1, x 2, x 4, x 8.

2-channel 12 bit analog output, with a maximum update rate of 1 MS/s and an output range of ± 10V or 0-10V (optional external reference).

24 channel TTL digital I/O (based on 8255 programmable peripheral interface, configurable as input/output/bidirectional port).

2-channel 16 bit universal timer/counter, with a base frequency of 40 MHz, supporting external clock (up to 10 MHz).

Analog and digital triggering, supporting pre triggering, post triggering, mid triggering, delayed triggering, and repeated triggering modes.

SSI (System Synchronization Interface) bus, used for multi card synchronous cascading and expanding the number of channels.

Fully automatic calibration, no need to manually adjust potentiometer, built-in ± 2 ppm/℃ temperature drift reference source.

Analog Input Front End Details

2.1 Differential Input and Anti Noise Capability

Each channel is a differential input with an input impedance of up to 1 G Ω | | 100 pF, which has minimal impact on the signal source. The typical value of Common Mode Rejection Ratio (CMRR) at gain=1 is 85 dB, which can effectively suppress ground loop and common mode interference. In terms of overvoltage protection, it can withstand ± 35V continuously without damage when powered on, and ± 15V when powered off, enhancing the fault tolerance of on-site wiring.

2.2 Input Range and Gain Combination

Through software programming, the range and gain of each channel can be independently set:

Bipolar: ± 10V, ± 5V, ± 2.5V, ± 1.25V;

Monopolar: 0~10V, 0~5V, 0~2.5V, 0~1.25V.

Gain of x 1, x 2, x 4, x 8, when combined with full range, can achieve smaller ranges (such as when ± 10V/8=± 1.25V, the resolution is correspondingly improved). For DAQ-2016/05/2006, the LSB of 16 bit resolution at ± 10V range is approximately 0.3mV (gain=1), which meets the requirements for most sensors to be directly connected.

2.3 Sampling rate and FIFO

DAQ-2010: Equipped with 8K sampling point FIFO, supports high-speed continuous acquisition, and reduces the risk of data overflow.

Other models: The FIFO has 512 sampling points, but data can be directly transferred to the system memory through Scatter Gate DMA, breaking the size limit of FIFO and achieving long-term continuous recording.

2.4 Trigger and Acquisition Modes

Supports multiple triggering sources (software, external digital/analog signals, SSI bus triggering) and provides flexible acquisition modes:

Pre trigger: Collect a specified amount of data before triggering (suitable for capturing the pre event state);

Post trigger: Collect data after triggering (most commonly);

Mid trigger: Simultaneously collect a segment of data before and after the trigger;

Delay triggering: Wait for a specified delay after triggering before collecting;

Repeated triggering: After a single trigger, repeat the collection multiple times, suitable for periodic signals.

Analog output and waveform generation

The two channel analog output uses a 12 bit multiplication DAC and supports the following output ranges:

Internal reference: ± 10V or 0-10V;

External reference: ± AO_deTREF or 0~AO_deTREF (up to ± 10V external reference can be connected).

Dynamic performance:

Update rate: 1 MS/s (1 μ s update interval);

Pendulum rate: 20 V/μ s, establishment time 3 μ s (up to ± 0.5 LSB);

Driving capability: ± 5mA (capable of driving capacitive loads up to 1500pF).

Analog output also supports triggering (software, external digital/analog, SSI), as well as post triggering, delayed triggering, and repeated triggering modes, which can achieve synchronous excitation signal output with analog input, forming a complete closed-loop testing system. The output FIFO size is 2K sampling points and also supports DMA transfer.

Digital I/O and Timer/Counter

4.1 24 channel digital I/O

Based on the classic 8255 chip, it can be programmed into three 8-bit ports (PA, PB, PC), each of which can be independently configured as an input or output. The PC port can also be further divided into two 4-bit half bytes. All signals are 5V TTL compatible and can be read and written through software polling, suitable for controlling relays, indicator lights, reading switch status, etc.

4.2 2-channel 16 bit timer/counter

Each channel supports:

Internal 40MHz reference clock (programmable frequency division);

External clock input (up to 10MHz);

Multiple modes: event counting, frequency measurement, pulse width modulation, square wave generation, etc.

Typical applications include speed measurement, pulse width measurement, and generating synchronous pulses.

Multi card synchronization (SSI bus)

When more than 4 analog input channels or 4 analog output channels are required, up to 4 DAQ-2000 series cards can be connected through the SSI (System Synchronization Interface) bus to achieve cross card synchronous sampling/updating. The SSI bus transmits the sampling clock, trigger signal, and synchronization status to ensure that all cards operate at the same time base with extremely low phase deviation between channels.

The matching SSI bus cables include ACL-SSI-2, ACL-SSI-3, and ACL-SSI-4, which support synchronization of 2, 3, and 4 cards respectively. When in use, simply connect the SSI interfaces of each card in series through cables and set the synchronization mode on the main card, and the slave cards will automatically follow. This is extremely practical for multi-channel array acquisition, such as sonar, radar, and multi axis vibration.

Software development and driver support

ADLINK provides a comprehensive software stack for the DAQ-2000 series:

D2K-DASK: Core driver and API library for Windows 98/NT/2000/XP/2003, supporting mainstream languages such as VB/VC+/BCB/Delphi.

D2K-DASK/X: Linux version, suitable for open source systems.

DAQ-LWIEW PnP: VI driver in LabVIEW for quickly building graphical programs.

DAQ-MTLB: MATLAB toolbox for algorithm validation and data analysis.

DAQPench: ActiveX control package, which allows drag and drop programming in Visual Studio.

All drivers support advanced features such as Scatter Gate DMA, automatic calibration, and trigger configuration, and provide rich sample programs to greatly shorten the development cycle.

Terminal board and wiring

The matching DIN-68S/1M terminal board provides a 68 pin SCSI-II connector and supports DIN rail installation. It comes with a 1-meter ACL-10568 shielded cable. Screw connection terminals are provided on the terminal board for easy connection of on-site sensors and actuators. It is recommended to use shielded twisted pair cables to connect analog signals and connect the shielding layer to the AGND of the terminal board at one end to reduce noise coupling.

Typical application cases

Multi channel dynamic signal acquisition: Four piezoelectric accelerometers are simultaneously connected to DAQ-2016, with a sampling rate of 800kS/s. They are used in conjunction with pre triggering to capture the waveform at the moment of machine tool impact for fault diagnosis.

Servo system characteristic testing: Use the analog output of DAQ-2010 to generate swept sine excitation (through AO0/AO1), and collect encoder or LVDT feedback signals through AI0-AI3 to measure the frequency response function.

Battery monitoring: DAQ-2006 samples 4 battery voltages (differential input) at 250kS/s, and combines digital I/O to control load on/off, achieving charge and discharge curve recording.

Multi card synchronous array: Two DAQ-2016 chips are synchronized through SSI to achieve synchronous acquisition of 8-channel vibration signals for large-scale structural modal analysis.

Calibration and maintenance

The DAQ-2000 series supports fully automatic calibration without the need for any external voltage source or potentiometer. Onboard high-precision reference source (temperature drift ± 2 ppm/℃, long-term stability 6 ppm/1000 hours), can be used to complete gain and offset correction of input/output channels by calling the AutoCalibration function in software. It is recommended to perform calibration once a year or when the ambient temperature changes by more than 10 ℃ to ensure accuracy indicators.

Daily maintenance precautions:

Regularly check if the cable connector (68 pin VHDCI) is loose or oxidized;

Avoid plugging or unplugging signal lines while they are live to prevent damage from overvoltage;

Maintain a working environment temperature of 0-55 ℃ and a relative humidity of 5-95% without condensation.

Common problems and troubleshooting

Discontinuity or loss of A/D acquisition data: Check the DMA buffer size and Scatter Gate settings to ensure that the application reads data in a timely manner; Reduce the sampling rate or increase the FIFO depth (DAQ-2010 only).

Trigger not responding: Confirm that the trigger source wiring is correct (TTL level is required for digital triggering, and within the input range for analog triggering); Check the trigger mode settings (if pre triggering, fill the FIFO first).

Multi card synchronous phase deviation: Ensure correct SSI cable connection, correct master/slave card jumper or software configuration; All cards use the same external clock source (such as SSI synchronous clock).

Analog output amplitude error: Perform automatic calibration; Check if the external reference voltage (if used) is stable.

Digital I/O read/write failure: Check the direction setting of port 8255 to ensure that the port is correctly configured as input or output.

If the problem persists, please use ADLINK technical support（ service@adlinktech.com ）Provide the board model, serial number, operating system and driver version, and fault reproduction steps.