In industrial control systems, it is common to have multiple signals transmitted simultaneously. However, during the transmission of multiple signals, “cross-talk” interference may occur, reducing the precision of the system control. In severe cases, it may even lead to system control failure, posing safety hazards.
1. On-Site Situation
Industrial environments often involve hazardous voltage, transient signals, common mode voltage, and unstable potentials, which can damage measurement systems and reduce measurement accuracy. To overcome these shortcomings, channel isolation modules are incorporated into the design of measurement systems in industrial applications. Channel isolation modules are particularly suitable when input signals come from different equipment or electrical environments, especially in harsh on-site electrical environments.
Taking a customer site as an example, when the customer used a regular current input module to collect frequency feedback signals from multiple frequency converters on-site, the complex on-site environment and the indiscriminate laying of cables, all connected through aviation plugs into the electrical cabinet, led to common mode interference between frequency converters and electromagnetic interference on-site, resulting in inaccurate data acquisition from the modules on-site. Finally, the customer solved the problem by adding isolation modules to the frequency converter signals for signal isolation.
2. Customer Requirements
Disadvantages of Non-Isolated Modules Between Channels:
The drawback of this acquisition scheme is that various analog signals coming from the industrial site have different ground potentials. There will inevitably be common-mode voltage differences between signals, and common-mode interference may cause crosstalk between signal channels.
3. ODOT Solution
In response to this situation, ODOT Automation has developed a new product, the 4-channel current input module—CT-3274.The CT-3274 current input module (0~20mA、4~20mA、-20~20mA), with a resolution of 15 bits, comes with channel isolation, greatly enhancing the module’s anti-interference performance. Customers do not need to install additional isolation modules.
Advantages of Channel Isolation Modules:
（1）Channel isolation modules can prevent mutual interference between multiple signals, ensuring no crosstalk between channels.
（2）The working mode voltage between channels allows up to 500V.
（3）Channels work independently, so a malfunction in one channel will not affect the normal operation of other channels.
The channel isolation module can individually isolate each channel of multiple input signals, eliminating the influence of common mode voltage and the crosstalk between channels, thereby enhancing system stability and improving anti-interference capability.
Post time: Apr-30-2024
