BRX PLC PID Ramp Soak Profile

The purpose of a ramp soak profile is to make gradual, controlled changes in temperature (Ramp), followed by a temperature hold (Soak) period.
We will be using our Proportional-Integral-Derivative PID Instruction with PWM output that we looked at last time to apply the ramp/soak profile.
Using the immersion heater in a cup of water to keep the temperature at a constant value, we will be adjusting the profile of the temperature as we increase the setpoint (Ramp) and hold that set point for a predetermined time. (Soak) We will then decrease that temperature back to the original setting. (Ramp)

We will be modifying our existing program from our PID with PWM Output post. Let’s get started. Continue Reading!

C-More EA9 HMI Series Panel Object List Clock

The C-More HMI Panel software uses virtual components called Objects. These objects are programmable to simulate the functions that you require on your automation project. Pushbuttons, Switches, meters, and graphs are just a few of the objects that are available to you.
The Clock Objects includes a couple of options to customize the display of a real-time clock (RTC) on a screen.

We will now look at the object list clock that we can use with our HMI panel. The clock objects that are available on the C-More EA9 are analog and digital. We will program each of these text objects. The source for the RTC clock will also be discussed and programmed both externally and internally. Let’s get started. Continue Reading!

BRX PLC PID with PWM Output

A Proportional-Integral-Derivative algorithm is a generic Control Loop feedback formula widely used in industrial control systems. A PID algorithm attempts to correct the error between a measured process variable and the desired setpoint by calculating and then outputting a corrective action that can adjust the process accordingly and rapidly, to keep the Error to a minimum.

Here are some references on PID control:
PID without a Ph.D. By Tim Wescott
Understanding PID in 4 minutes
PID Control – A brief introduction
PID Controllers Explained
Who Else Wants to Learn about On-Off and PID Control?
We will be using an immersion heater in a cup of water to keep the temperature at a constant value. Using the Do-More Designer software we will perform an autotune on our PID instruction.
Our immersion heater will be controlled through a relay using time proportional control from our PID output. Let’s get started! Continue Reading!