Maintaining effective and efficient control of temperature-sensitive processes like pasteurization, cooling, and cooking can be a challenge for Food & Beverage manufacturers. These processes rely on consistent temperature management to meet strict quality, safety, and regulatory requirements. Even slight fluctuations in temperature can lead to costly consequences such as spoiled batches, non-compliance with safety standards, or inconsistent production quality.
Complexities in the Food & Beverage sector often stem from the multivariable and interactive nature of temperature processes. It’s not uncommon for temperature controllers to fight with the competing dynamics of other temperature, flow, and pressure loops. Keeping the PIDs that are responsible for regulating temperature within their designated ranges can be difficult under the best of circumstances.
If achieving and maintaining effective temperature control presents a challenge for you and your facility’s operation, then consider the following:
- Oscillations: Control loop oscillations can be particularly problematic in temperature processes as they drive fluctuations that can compromise product integrity. As examples, maintaining tight temperature within pasteurizing processes is critical for food safety, and maintaining accurate temperature while tempering chocolate ensures both quality and the perfect “snap”. Oscillations make it challenging to meet those requirements.
When tuning temperature control loops, consider the use of Derivative to counter the negative influence of oscillatory behavior. Though it can be counterproductive in processes that are noisy, Derivative is often ideal for use with PID control loops that are slow to respond and that exhibit a large Dead-Time.
- Signal Noise: A common issue with all types of control loops is signal noise which can obscure or distort a process’ true dynamic behavior. Essentially, signal noise is the result of electrical interference from sensors and other instrumentation that becomes comingled with the data values associated with a process. Signal noise is high frequency which can interfere with the accurate modelling and tuning of PID loops, leading to ineffective control.
While signal noise influences a temperature process’ data, the variability that it represents does not actually come from the process itself. Rather, it is just a form of electrical interference that can and should be corrected through normal maintenance procedures.
- Valve Stiction: The leading mechanical issue faced by production staff is Stiction. Stiction refers to a control valve’s inability to move smoothly and incrementally in the correction of Error. It can be the unfortunate result of a valve that is packed too tightly. Stiction often results in inconsistency which is particularly harmful to quality-sensitive temperature processes not to mention the unnecessary wear and tear on the valve itself.
If Stiction is present in a temperature process, then ample evidence should be available in the process data. Monitoring the performance of your PID controllers can allow Stiction to be pinpointed on a proactive basis, limiting its impact on both production quality and asset reliability.
Experts in Temperature Control
At Control Station, we’re experts in process control and we understand the unique challenges faced manufacturers in the Food & Beverage industry – particularly with temperature control. We’ve developed innovative and intuitive tools such as LOOP-PRO Tuner and PlantESP that simplify the identification and correction of common PID controller challenges, allowing food manufacturers to satisfy regulatory requirements while also positioning them to maximize throughput and quality.
Learn more about our solutions here.
