Micromod Micro-DCI: 53SL5100B Single Loop Controller Uživatelský manuál stáhnout pdf (Strana 85)

53SL5100B Single-Loop Controller

INSTRUCTION MANUAL

11.5 Modifications to Tuning Criteria

During EASY-TUNE sequence execution, each of the three algorithm variables: Time Constant (TP ), Process

Gain (K

P), and Dead-Time (WP), are altered by 10% in the conservative direction, (instrument operating

characteristics would be slower response, but less chance of oscillation and instability) before the tuning

parameters are computed using the ITAE equations listed in Table 11-4. (Figure 11-2 illustrates the equation

variables with respect to the response curve.)

The three variables T

P, KP, and WP can be increased numerically to compute tuning parameters that are

more conservative, or decreased for less conservative tuning parameter calculations (instrument operating

characteristics would be faster response and greater chance of instability or oscillation). Parameters used to

alter the variables are the EASY-TUNE Modifiers, datapoints C382 (T

P Modifier), C383 (DP Modifier), and

C384 (W

P Modifier). It is recommended that the values entered in C382, C383, and C384 be between -0.5

and 0.5. The effect on the equation variables is as follows:

P modified = TP (1 - C382)

P modified = KP (1+ C383)

P modified = WP (1+ C384)

Table 11-3. EASY-TUNE Equations

Mode PB in % TR (Minutes) TR* (Minutes)

P 204K

)

1.084

0 0

PI 116.4K

)

0.977

/40.44)(W

)

0.68

PID 3.69K

)

0.947

/51.02)(W

)

0.738

/157.5)(W

)

0.995

PD** 54.02K

)

0.947

0 (T

/157.5)(W

)

0.995

i** 0 T

[(K

/25)(W

)

0.15

] 0

 NOTE: Process characteristics TP, KP, and WP are used to compute the ideal tuning parameters

according to the Minimum Integral of Absolute Error Multiplied by Time Criterion (ITAE) for P, PI, and

PID modes.

*If computed to be < B003/50, then TD = 0.

**Empirical estimates, not based on ITAE method.

 NOTE: The approximation of a process step response curve by a first order time lag plus dead-

time model is done by equating their values at 0.2835 and 0.6321 fraction of the total excursion.

1 2 ... 80 81 82 83 84 85 86 87 88 89 90 ... 114 115

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