Allen-Bradley SLC 500 Series

Publication 1747-RM001G-EN-P - November 2008
9-6 Proportional Integral Derivative Instruction
Controller Gain (K
c
)
Gain K
c
(word 3) is the proportional gain, ranging from 0 to 3276.7 (when RG
= 0), or 0 to 327.67 (when RG = 1). Set this gain to one-half the value needed
to cause the output to oscillate when the reset (T
i
) and rate terms (T
d
) (below)
are set to zero.
Reset Term (T
i
)
Reset Term T
i
(word 4) is the Integral gain, ranging from 0 to 3276.7 (when
RG = 0), or 327.67 (when RG = 1) minutes per repeat. Set the reset time equal
to the natural period measured in the above gain calibration. A K
c
value of 1
adds the maximum integral term into the PID equation.
Table 9.3 Controller Gain Parameter
Tuning Parameter
Descriptions
Address Data Format Range Type User
Program
Access
KC - Controller Gain Word 3 word (INT) 0 to 32,767 control read/write
TIP
Controller gain is affected by the reset and gain range (RG)
bit. For information, see Reset and Gain Enhancement Bit
(RG) on page 9-10.
Table 9.4 Reset Term Parameter
Tuning Parameter
Descriptions
Address Data
Format
Range Type User Program
Access
TI - Reset Term - T
i
Word 4 word
(INT)
0 to 32,767 control read/write
TIP
Reset term is affected by the reset and gain range (RG) bit.
For information, see Reset and Gain Enhancement Bit (RG)
on page 9-10.