Configuration
3/07 UDC3500 Universal Digital Controller Product Manual 83
Function Prompt
Lower Display
Selections or
Range of Setting
Upper Display
Parameter
Definition
F FWRD
(Standard feature on
controllers with two or
more analog inputs)
FEEDFORWARD SUMMER—Feedforward uses
Input A, following a Ratio and Bias calculation, as a
value summed directly with the PID computed output
value and sent, as an output value, to the final
control element.
This algorithm will only function in automatic mode
and is not used for Three Position Step Control
applications. Algorithm 1 Feedforward works only on
Loop 1 while Algorithm 2 Feedforward works only on
Loop 2.
The following formula applies:
Controller Output = PID Output + (Input A x Ratio A + Bias A) x (100 / Input A
Range)
FFWDMu
(Standard feature on
controllers with two or
more analog inputs)
FEEDFORWARD MULTIPLIER—Feedforward uses
Input A, following a Ratio and Bias calculation, as a
value multiplied directly with the PID computed
output value and sent, as an output value, to the final
control element.
This algorithm will only function in automatic mode
and cannot be used for Three Position Step Control
applications. Algorithm 1 Feedforward works only on
Loop 1 while Algorithm 2 Feedforward works only on
Loop 2.
The following formula applies:
Controller Output = PID Output x (Input A x Ratio A + Bias A) / Input A Range
RELHUM
(Standard feature on
controllers with two or
more analog inputs)
RELATIVE HUMIDITY—Input 1 reads the wet bulb
temperature. Input 2 reads the dry bulb temperature.
The controller will indicate measured Relative
Humidity as a Process Variable (PV) with a Setpoint
range of 0 % to 100 % RH.
ATTENTION The Relative Humidity selection will
automatically force both Input 1 and Input 2
actuations to the RTD 100 ohm low setting.
See Note 6.
SUMMER
(See Note 2)
SUMMER WITH RATIO AND BIAS—The following
formula applies:
Alg1 = (Input A x Ratio A + Bias A) + (Input B x Ratio B + Bias B) + (Input C x
Ratio C + Bias C) + Alg1Bias
HI SEL
(See Note 2)
INPUT HIGH SELECT WITH RATIO AND BIAS—
This selection specifies the PV or SP as the higher
of Input A or Input B. The following formula applies:
Alg1 = higher of (Input A x Ratio A + Bias A) or (Input B x Ratio B + Bias B)