PLC Programming: Perplexed by Programming PID Loops in Your PLC?
Simplify with Intuitive Function Blocks
by John N. McMurray
Any type of PLC programming can be a challenge, and turning PID loops into web applications can be tedious enough. But when you also have to write the PLC code to implement PID functions, the task becomes even more difficult (and expensive). Choosing from many algorithms, converting machine information (e.g., motor speed, line speed, web tension, package diameter) to PLC-friendly form, writing code, debugging the program, and then actually tuning for constantly-changing system dynamics, all present costly and time-consuming challenges.
If a standard, proven product is easily available for PLC programming that already incorporates the desired PID functions, and is simple to program, it would be a cost-effective solution to a very frustrating problem. If, in addition to functionality, the device offers pre-conditioned inputs and outputs, RS-485 communication protocol, an interface port for common HMIs, and provides an Application Builder for easy setup, the best decision may be to replace your PLC loop programming and interface hardware with this dedicated function block.
The CORTEX® LT by Carotron, Inc. is a general-purpose micro-controller with the flexibility to meet this application. Driven by a powerful DSP (digital signal processor) the unit has the speed and processing capability to handle even the most difficult tasks. There is also built-in circuitry for up to two ultrasonic range sensors, so that extra input signal-conditioning hardware is not needed.
Each Cortex® LT is supplied with MS-Windows (98 and higher) compatible CORTEX® LT Link Software and a serial cable for interface between the CORTEX® LT and an RS-232 port on a PC. The Link Software allows a specific application programming (PLC programming) to be selected, configured, and downloaded to the CORTEX® LT hardware. The Link Software also allows for calibration, monitoring, program storage and I/0 simulation.
The “LT Builder” provides an easy, simplified configuration guide for standard application selections. Through a series of application questions, the “LT Builder” pulls together the application blocks to perform the desired tasks. Advanced users can also access the system blocks directly and link functions for modifications to the standard configurations. System Blocks are displayed graphically in the Link Software to aid in understanding the functions to be performed by each block.
The CORTEX® LT works with virtually all industrial drives that might have need of PLC programming: AC Inverters, DC Drives, Hydraulic Motors w/ Servo Valves, and Eddy-Current Couplings.
Visit the main product page for the CORTEX® LT for more information. Contact Carotron, Inc. toll free at 1-888-286-8614 and let us review your application and offer the right components to do the job. We want to help you with PLC programming and PID loops so you can save time and money!