PACTECH / ICP DAS (Vol. EC01_2016, By Michael Lai)
In automation applications for hydraulic systems, the PLC is usually used to perform the interlocking controls for various valves so that the hydraulic system can function accurately, such as proportional valves, solenoid valves and pressure reducing valves. The driving input range for each valve or switch may vary. Some require an input voltage for control operations of -10 to +10 V, and some may require 4 to 20 mA. However, most PLCs do not support such a large variety of signal output types and ranges, thus causing difficulties in system design and implementation.
The ICP DAS WISE-7126 module offers two DI channels, two DO channels, six AI channels and two AO channels, and is equipped with functions that perform a linear conversion of the AI channel input value, which can then be forwarded to the AO channel for output operations. Thus, by using the WISE-7126 module as a signal converter between the PLC and the proportional valves, it offers an easier, faster and more flexible method of implementing hydraulic system applications.
In this scenario, the PLC used only supports -10 to + 10 V voltage output, and the input current range for the proportional valve is 4 to 20 mA. AI channel 0 on the WISE-7126 module is connected to the output of the PLC, and AO channel 0 on the WISE-7126 module is connected to the proportional valve.
On the web configuration interface for the WISE-7126, you can configure the input signal type as “voltage”, and set the input range to “-10V to + 10V” for AI channel 0. The input range value will then be converted from “-10 to 10” to “4 to 20” using linear conversion. Configure the output signal type to be Current and the range to be 4 to 20 mA for AO channel 0. Finally, configure the IF-THEN-ELSE logic rule so that the value from AI channel 0 can be forwarded to AO channel 0 to output the value. By using the WISE-7126, the signal conversion between the voltage and the current, and the corresponding control between the PLC and the proportional valve can be easily carried out.
* No programming required to implement the logic settings for the system
* Quickly establish a system, dramatically reducing the labor and costs spent on system development
* Supports multiple input and output voltage and current ranges, and the values can be freely converted by configuring a few simple parameters in the settings
* Includes an easy-to-use settings and monitoring webpage for real-time information access
ICP DAS was established in 1993 and strongly focuses on innovation and the enhancement of industrial automation technology. ICP DAS continuously endeavors to develop a comprehensive selection of products ranging from remote I/O controllers, distributed I/O modules, I/O data acquisition boards, programmable automation controllers, industrial communication modules, web-related products, motion control systems, SCADA/HMI software to automation solutions for applications critical to energy management, motion automation, smart factories, intelligent buildings, and smart cities. Our ambition is to provide a wide range of high-quality products and versatile applications, together with prompt and efficient services, that can be implemented to assist in the continued success of our clients worldwide.