model 2704 controller installation and operation handbook - Soliton
model 2704 controller installation and operation handbook - Soliton
model 2704 controller installation and operation handbook - Soliton
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Tuning<br />
<strong>2704</strong> Controller<br />
8. Chapter 8 Tuning<br />
This chapter describes how to tune your <strong>controller</strong> to match the characteristics of the process<br />
under control.<br />
There are four topics:<br />
• WHAT IS TUNING?<br />
• AUTOMATIC TUNING<br />
• MANUAL TUNING<br />
• GAIN SCHEDULING<br />
This chapter should be read in conjunction with Chapter 9, Loop Set Up.<br />
8.1. WHAT IS TUNING<br />
In tuning, you match the characteristics of the <strong>controller</strong> to those of the process being<br />
controlled in order to obtain good control. Good control means:<br />
• Stable, ‘straight-line’ control of the PV at setpoint without fluctuation<br />
• No overshoot, or undershoot, of the PV setpoint<br />
• Quick response to deviations from the setpoint caused by external disturbances, thereby<br />
rapidly restoring the PV to the setpoint value.<br />
Tuning involves calculating <strong>and</strong> setting the value of the parameters listed in Table 8-1. These<br />
parameters appear in the Loop Setup (PID) list, see Chapter 9.<br />
Parameter<br />
Meaning or Function<br />
Proportional<br />
b<strong>and</strong><br />
Integral time<br />
Derivative time<br />
High Cutback<br />
Low cutback<br />
Cool gain<br />
The b<strong>and</strong>width, in display units or %, over which the output power is<br />
proportioned between minimum <strong>and</strong> maximum.<br />
Determines the time taken by the <strong>controller</strong> to remove steady-state error<br />
signals.<br />
Determines how strongly the <strong>controller</strong> will react to the rate-of-change of<br />
the measured value.<br />
The number of display units, above setpoint, at which the <strong>controller</strong> will<br />
increase the output power, in order to prevent undershoot on cool down.<br />
The number of display units, below setpoint, at which the <strong>controller</strong> will<br />
cutback the output power, in order to prevent overshoot on heat up.<br />
Only present if cooling has been configured <strong>and</strong> a module is fitted. Sets<br />
the cooling proportional b<strong>and</strong>, which equals the proportional b<strong>and</strong> value<br />
divided by the cool gain value.<br />
Table 8-1: Tuning Parameters<br />
8-2 Installation <strong>and</strong> Operation H<strong>and</strong>book. Part No HA026502 Issue 1.0 Apr-00
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