v 1.0 — August 2018 Altanium Neo5
Page 88
7.5.14.1 Changing the Zone Control from ART to PID
The control algorithm is automatically adjusted to suit different heater requirements. This
control method is referred to as Active Reasoning Technology (ART). In some cases, it may be
necessary to switch from the automatically adjusted ART algorithm to an algorithm that can
be manually adjusted. This control method is referred to as PID. When switching a zone from
ART control to PID control, you can manually enter values for the Proportional, Integral and
Derivative parameters.
7.5.14.2 Typical PID Values
The following is a list of some typical PID values.
7.5.14.3 Possible Causes of Oscillation
It is possible to set the control terms incorrectly, which causes an oscillation. The most
common causes of oscillation are:
PID Values
Proportional Integral Derivative Type Example
015 010 002 Fast Probes or heaters with internally located
thermocouples
050 020 000 Fast
020 010 000 Fast
015 015 000 Fast
020 007 100 Medium Probes or heaters with internally located
thermocouples (larger mass)
020 005 200 Medium
100 003 000 Slow Manifolds or heaters with externally
located thermocouples
075 003 150 Slow
Possible Causes of Oscillation
Cause Description
“P” too large Power change too great per °C of temperature change.
“I” too large Power changing too quickly for the process to follow it.
“D” too large Stepped power change too large for the rate of change of temperature.
Shear An important issue often overlooked is the effect of shear in the material as
it passes through the gating area. This can cause rises in temperature in
excess of 33 °C (60 °F) under severe conditions. Therefore, if large
temperature variations occur during molding, it is worth plotting this
variation against the molding cycle time. As the controller cannot initiate
additional cooling, it is only possible to minimize this effect with properly
selected PID terms.
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