Modern industrial systems such as robotics and automated conveyor systems rely on high-speed, synchronized data to optimize performance, improve efficiency, and achieve predictive maintenance. However, capturing and coordinating position and motion data with millisecond level accuracy is a major challenge. Standard data acquisition (DAQ) systems often lack the specialized functionality required for real-time connection with encoders and timers, which can lead to decreased system reliability and performance bottlenecks.
This article first briefly introduces the various requirements required for high-speed measurement of position and time in harsh industrial applications. Subsequently, Advantech's encoder counter/timer module is introduced, and the various encoder modes and four high-speed channels of this module are explained how they can be used to solve complex synchronization problems in robot and motion control applications. Typical system configurations and compatible software tools provide a clear implementation path for system integration.
The importance of precise control of motion and time in industrial processes
Modern industrial systems rely on complex and orderly movements, in which coordination ability is crucial. Let's consider a robotic arm that picks up components from a moving conveyor belt. In order for the system to operate normally, the movement of the robotic arm must be synchronized with the speed and position of the conveyor. To achieve this, it is necessary to capture information from multiple data sources with millisecond level accuracy and coordinate it, which is a highly challenging technical requirement.
The DAQ system plays a central role in solving this problem. The system captures encoder data from the drive motor of the conveyor and the joints of the robotic arm, and synchronizes these measurements in multiple channels to accurately calculate the timing of intercepting items on the conveyor belt.
When increasing the speed of the conveyor belt to improve production efficiency, the data acquisition system (DAQ) must quickly sample position and time data to avoid errors. Delayed or missing sensor readings may lead to incorrect timing of mechanical component operation, and even cause collisions between mechanical components, resulting in unexpected shutdowns and loss of productivity.
The high-precision DAQ system also supports predictive maintenance. For example, abnormal speed or position error may indicate a problem, such as bearing wear or belt slippage. By analyzing these signals, designers can identify potential faults in advance and avoid operational interruptions.
Requirements for high-speed DAQ
To meet these application requirements, DAQ systems must possess the following key performance characteristics:
High speed and high-resolution sampling: Capturing subtle movements, such as sub millimeter level position changes, requires both high sampling rates and high-precision resolution. Sampling in the megahertz (MHz) range ensures that no critical events are missed even in high-speed environments.
Multi channel simultaneous sampling: In order to coordinate the operation of the robotic arm and conveyor belt, it is necessary to capture their respective position and time data simultaneously, rather than capturing them sequentially. Attempting to correlate sequentially captured data streams may result in errors, such as selecting the wrong item on the conveyor belt or completely missing that item.
Flexible encoder support: Industrial systems often use components from different suppliers, resulting in mixed encoder signal types. The DAQ system should support multiple encoder modes to avoid adding interface logic.
Industrial design: Industrial environments can expose electronic devices to harsh conditions such as electromagnetic interference, vibration, and high temperatures. Therefore, in order to ensure reliable system operation and prevent system failures, appropriate DAQ hardware must be used.
Scalability: DAQ systems should adopt modular design, allowing designers to easily expand the system by adding more channels or different types of inputs. This means that even as automation facilities continue to expand, the integration of new robots, sensors, and production lines can still be ensured.
To meet this diverse range of needs, it is necessary to face the significant design challenges that come with it. Although many DAQs are highly suitable for general data acquisition, application criteria involving high-speed, synchronous motion require specialized hardware.
Advanced position and time measurement technology for motion control systems
The iDAQ-784 high-precision encoder counter/timer module (Figure 1) launched by Advantech is designed specifically to meet these requirements. This module provides four universal 32-bit encoder channels, which can support synchronous measurement of position and time in industrial systems. This module supports input frequencies up to 10 MHz to achieve precise timing of encoder signals.
Advantech's iDAQ-784 Encoder Counter/Timer Module
Figure 1: The iDAQ-784 encoder counter/timer module supports simultaneous data acquisition on four 32-bit channels, making it suitable for complex industrial motion control applications. (Image source: Advantech)
The built-in digital signal filtering function can help iDAQ-784 achieve clearer signal transmission and higher measurement accuracy. This provides high-precision system level characterization capabilities for advanced automation applications, such as industrial robots, motion control systems, and high-speed conveyor systems.
Input, measurement, and output modes of encoder
IDAQ-784 supports multiple input signal types and measurement modes to meet diverse industrial motion control needs. Each counter channel supports single ended and differential inputs, with a common mode voltage range of ± 15 VDC. This module supports three industry standard encoders for position measurement:
Orthogonal (A/B phase): By using two signal channels (A phase and B phase) with a phase difference of 90 °, the position and direction are synchronously determined. The specific encoding method (X1, X2, or X4) determines the resolution by counting the number of rising and/or falling edges, where X4 has a resolution four times that of X1.
Dual pulse (CW/CCW): Clockwise (CW) and counterclockwise (CCW) pulses use separate input lines. The counter increments under CW pulse and decrements under CCW pulse.
Pulse direction (signed pulse): One signal is used to generate a pulse, while the other signal indicates the direction. The counter increments or decrements based on the state of the directional signal.
Each encoder input can use single ended or differential wiring, and provide a Z signal input for position reset. Each counting channel also supports multiple functional modes for timing and pulse generation:
Event Count: Count the rising or falling edge of the input signal, with optional gating function.
Frequency measurement: Accurately measure the signal frequency using the inverse cycle method or pulse counting method.
Pulse width measurement: measures the duration of high and low levels of a digital signal.
Position measurement: Track the encoder position using the supported input modes mentioned above.
Continuous comparison (position comparison): When the position threshold is reached, an output pulse or interrupt is triggered.
Single trigger (delayed pulse generation): After gate triggering and a specified delay, output a single pulse.
Timer/Pulse Generation: Output a continuous pulse train with interrupt support function.
Pulse width modulation (PWM): outputting waveforms with programmable high and low level durations; Supports limited or continuous generation.
This extensive mode selection ensures compatibility with various common devices in industrial systems.
Specially designed for industrial environments
The iDAQ-784 and its surrounding ecosystem are designed to achieve high reliability in harsh industrial environments. The rated operating temperature range of this module is -40 ° F to 158 ° F, with a relative humidity of up to 90% (non condensing).
In addition, this module is specifically designed to resist common electromagnetic interference in factory environments; Its built-in digital signal filter can improve signal clarity, and each channel supports differential signal input, achieving excellent common mode noise suppression performance.
This design concept also extends to ecosystem accessories, which adopt sturdy and durable designs that comply with DIN rail standards and can be reliably installed in industrial cabinets. With the powerful combination of environmental tolerance, noise resistance, and robust physical integration, high-precision system level characteristic analysis can be performed on advanced automation applications.
Building a high-speed and high-precision DAQ system
The first step in building a DAQ is to connect the sensors. Firstly, connect the sensor leads to the wiring terminals. Advantech's ADAM-3937-BE interface module (Figure 2) is a ready-made solution for this purpose. This 37 pin module is designed specifically for DIN rail installation, with dimensions of 87.2 mm x 112.5 mm x 51 mm, and can be easily integrated with standard DB37 compatible industrial infrastructure.