High-Performance Data Acquisition System
Hardware selection and performance optimization
Keywords: Data Acquisition (DAQ), High-Speed Scan, Flexible, Versatile, Power Management, High Voltage
When building a high-performance data acquisition (DAQ) system, developers often need to make trade-offs between sampling rate, measurement stability, and expansion cost. GW Instek's DAQ-9600 adopts a 3-slot host architecture and integrates a 6.5-digit precision multimeter (DMM), aiming to maintain extremely high measurement accuracy at high channel density.
The following section explains the key features of each module in the DAQ-9600 to help you select the appropriate module to build a high-efficiency system:
1. DAQ-900 (High-Speed Scan): Suitable for automated testing environments requiring rapid and high-volume temperature recording.
• Scanning speed up to 450 channels per second, the fastest among all modules.
• Employs solid-state relays, eliminating mechanical contacts and wear, providing high-speed response and reducing downtime due to component replacement.
• Built-in cold junction temperature reference, suitable for applications requiring rapid and high-volume temperature recording.
2. DAQ-901 (Flexible and Versatile): Suitable for scenarios requiring the measurement of multiple different signals and demanding flexibility in measurement configuration.
• Mixed Measurement Capability: The same module can use both 2-wire and 4-wire channels.
• Built-in Current Measurement: Provides two additional current channels (maximum 1 A), allowing direct measurement without the need for external shunt resistors, simplifying wiring time.
• Scanning speed of 80 channels per second, providing a 300V switching voltage.
3. DAQ-903 (High-Density Channels): Suitable for common-low applications such as battery testing or component characterization.
• Maximized Channel Count: A single module provides 40 channels (single-ended common ground), and a single DAQ-9600 with three modules installed can reach 120 channels, maximizing the sample size for a single measurement.
• Suitable for common-low applications such as battery testing and component characterization.
4. DAQ-904 (Flexible Switching): Suitable for complex test systems requiring frequent switching between multiple test points and different instruments.
• Flexible Connection: The 4 x 8 matrix allows different instruments to be connected to multiple points on the DUTs simultaneously, with a switching speed of only 3ms.
• Larger matrices (such as 8 x 8) can be created through series connection, with a maximum of 96 crosspoints per unit.
5. DAQ-907 (Sensing and Control Integration): Suitable for automated monitoring systems requiring a high degree of integration between sensing and control functions.
• Digital and Analog Integration: Includes 16-bit digital I/O, a 100 kHz accumulator, and analog outputs (±12 V or ±24 mA).
• Real-time Alarm Recording: Alarms can be retrieved even between scans, enhancing the responsiveness of automated testing.
6. DAQ-908 (Power Management): Dedicated for controlling the power status of the DUT.
• Independent relay control: Features 20 independent single-pole double-throw (SPDT) relays for cyclic power supply, indicator light control, or activating external high-power relays.
• Handles switching power up to 50 W, suitable for building customized automatic switching systems.
7. DAQ-909 (High Voltage Reader): Suitable for high-power testing environments, eliminating the complexity of external adapters.
• High Voltage Design: Supports DC 600 V / AC 400 Vrms voltage measurement.
• Large Current Direct Reading: Two additional current channels allow direct measurement of 2 A current without the need for an external shunt.
8. DAQ-919 (kV High Voltage): Designed for DC high-voltage measurement environments, eliminating the need for an external voltage divider. Suitable for applications such as AI server power supplies and EV chargers with ±400 V or 800 V systems.
• High Voltage Design: Supports DC 1000 V voltage measurement.
| Model Descriptions | Types |
Speed |
Max. Voltage | Max. Current | Bandwidth | Thermal Offset | Remarks |
|
DAQ-900 20-Channel Universal Multiplexer |
Solid State Relay (Optional 2/4 Wire) | 450 | 120 V | 10 MHz | < 4 μV | Built-in reference cold junction | |
|
DAQ-901 20-Channel Universal + 2 Current Channel Multiplexer (Total 22 Channels) |
Armature Relay (Optional 2/4 Wire) | 80 | 300 V | 1 A | 10 MHz | < 4 μV | Built-in reference cold junction 2 additional current channels |
|
DAQ-903 40-Channel Single-Ended Multiplexer |
Armature Relay (common low) | 80 | 300 V | 10 MHz | < 1 μV | No 4-wire measurement | |
|
DAQ-904 4 x 8 Matrix |
Armature Relay | 300 V | 10 MHz | < 1 μV | |||
|
DAQ-907 Multi-Function Multiplexer |
16-bit Digital Input and Outputs | 42 V | Open drain | ||||
| 100 kHz Accumulator Input | 42 V | 100 kHz | Selectable input threshold | ||||
| Two 18-bit Analog Outputs | ± 12 V | ± 24 mA | Maximum 40 mA total output per module | ||||
|
DAQ-908 20-Channel Actuator/General-Purpose Switch |
SPDT/form C | 300 V | 10 MHz | < 4 μV | |||
|
DAQ-909 8-Channel High-Voltage + 2-Channel High-Current Multiplexer (Total 10 Channels) |
Armature Relay (Optional 2/4-wire) | 60 | DC 600 V AC 400 V |
2 A | 10 MHz | < 4 μV | 2 additional current channels |
|
DAQ919 8-Channel High Voltage Multiplexer |
Armature Relay | 60 |
DC 1000 V |
10 MHz | < 4 μV |
Key Recommendations for Building a High-Efficiency System
• Software Automation: Utilizing GW Instek's free DAQ software, results can be recorded and visualized through various display options, accelerating the data analysis process.
• Interface Selection: The system comes standard with LAN, USB, and Digital I/O interfaces. For existing infrastructure needs, a mini GPIB can be purchased to ensure efficient data transfer with the computer.
• Accuracy Guarantee: The system features a sampling rate of up to 38.4 k SPS and 100 k non-volatile memory, ensuring a basic DC voltage accuracy of 0.0035% even at high-speed measurements.
By precisely selecting the modules mentioned above, you can optimize time costs for your testing objectives (e.g., DAQ-900 prioritizes scan speed, DAQ-903 prioritizes channel density), thus establishing a highly efficient and stable automated testing system.
In addition to appropriate hardware selection, optimizing a data acquisition (DAQ) system to improve efficiency (especially measurement speed and data volume) can also be achieved by focusing on three aspects: parameter configuration, transmission latency, and specific measurements.
1. Optimize Parameter Configuration to Reduce System Waste Improper settings can lead to unnecessary processing time. Here are some optimization suggestions:
• Disable the host display: During automated testing, the front panel display can be turned off remotely to reduce the resources required for host display processing.
• Set an appropriate resolution: Choose a resolution sufficient for your needs. For example, if 5.5 digits are sufficient, there's no need to set it to 6.5 digits to save processing time.
• Fix measurement ranges/parameters: Avoid using automatic range switching, as the host consumes extra time determining the correct range for each measurement. This is especially important when multiple parameters are involved in the measurement process (e.g., voltage, temperature, etc.).
• Optimize integration time (PLC): Select the correct power line cycle (PLC) integration time based on noise suppression requirements. Finding the optimal balance can save hundreds of milliseconds per reading.
2. Reduce Transmission and Transaction Latency
• Consolidate Command Strings: Instead of sending commands one at a time, concatenate multiple commands together (e.g., ROUT:CLOS; :ROUT:OPEN;). This can significantly reduce transaction latency, saving up to 50% of transaction time.
• Offload Computation to the Computer: For example, when measuring temperature, if the program's capabilities permit, the mathematical calculation of converting voltage to temperature can be handled by the computer instead of the DAQ host.
3. Optimization Techniques for Specific Measurement Categories
Temperature Measurement:
• Sensor Selection: Thermocouples are generally faster than thermistors or RTDs because they output voltage.
• Reduce Reference Contact Measurement Frequency: Reduce the number of times thermocouple cold contacts are measured to gain more measurement time.
Resistance Measurement:
• Voltage Measurement Mode: When using a constant current source, the DAQ can be set to measure only voltage, and the resistance can be calculated on the computer using Ohm's Law, optimizing the resistance measurement speed.
Current Measurement:
• For multi-point current measurement requirements, traditional external shunt resistors often introduce variations in contact resistance due to inconsistent terminal tightening torque. The DAQ-909 module provides dedicated shunt resistor pads on the PCB, allowing users to directly solder high-precision resistors onto the module. This approach not only eliminates errors caused by mechanical connections, but also enables the module to function as a dedicated multi-channel current acquisition module.
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Note SHUNT recommends:
• For mA current measurement : 1 Ω
• For A current measurement (not recommended to exceed 2 A) : 0.1 Ω
When using DAQ-Data Logger software, select DCV as the function, and then use MX+B to convert the numerical result to current units (A).
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Contact Us:
Diana
Digital Service Specialist
E-mail: diana@goodwill.com.tw