PCC-IV Instruction Manual (Rev. 0.1)
Page 6-29
Section 6
– Blockware Functions
Technical Reference
Positioner Mode
is used to position a reversible electric actuator that is equipped with a position feedback signal
(potentiometer, 0-5 Vdc, or 4-20 mA).
TOUT
compares the Setpoint Input to the Scaled Position, if the difference is
outside of the Deadband (Parameter. 7), one of the two Triac outputs is turned ON to drive the actuator toward the
Setpoint position. When the actuator position is within the range of: (Se/- Deadband), both Triacs are turned
OFF. In Positioner Mode, the Triac 1 and Triac 2 Inputs are ignored. The Block Output of
TOUT
is the
0-100% Scaled Position of the actuator. See the diagram below for a typical Positioner Mode application.
PCC-IV Blockware
N
INC
DEC
INC
DEC
MOTOR
POSITION
FEEDBACK
POT
REVERSIBLE ELECTRIC ACTUATOR
TYPICAL F83 (TOUT) 'POSITIONER' MODE APPLICATION
1-48
+5
1-48
+5
1-49
+
1-49
+
1-51
-
1-51
-
1-42
inc
1-42
inc
1-43
dec
1-43
dec
1-44
N
1-44
N
1-44
PS N
1-44
PS N
1-40
PS H
1-40
PS H
HOT
NEUTRAL
Scaled Position (Positioner Mode): The actuator position feedback signal must be connected to a PCC-IV Analog
Input channel (typically on a "G" Option Board). The
AIN
Block for this channel is then connected to the
TOUT
Block Feedback Input. For Potentiometer position feedback signals, the
AIN
Block Scaling Parameter values should
be 0V = 0 % and 5V=100%. The
AIN
FILTER SECONDS (Parameter 6)
MUST
be set to 0.0 seconds, larger values
will cause the actuator to hunt or oscillate.
TOUT
Parm. 4 & 5 are used to convert the unscaled
AIN
Feedback Input to a 0-100%
TOUT
Scaled Position.
Example:
AIN
= 25% at minimum position, AIN = 75% at maximum position. Set Parameter 4 (0% feedback) =
25%, and Parameter 5 (100% feedback) = 75%. When: Feedback Input = 25%,
TOUT
Block Output = 0%;
Feedback = 35%,
TOUT
= 20%; Feedback = 45%,
TOUT
= 40%; … Feedback = 75%,
TOUT
= 100%.
For '"fail open" applications P4 (Parameter 4) can be greater than P5, that is: P4 (0% feedback) = 75%, and
P5 (100% feedback) = 25%.
Use S/M for Initial Actuator Setup (Positioner Mode): After the actuator electrical installation is completed, put the
PCC-IV into S/M mode (Service Manual, see Section 4), and go to the Service Manual submenu for
Change one
output.
Select the applicable TOUT channel (Triac Output, Board x, Channel y). Press the INC key to open/increase
the actuator; press the DEC key to close/decrease the actuator.
Calibrating the Scaled Position (Positioner Mode): Read "Scaled Position", "Initial Actuator Setup", and "Are Bias
Resistors Required" sections of
TOUT
before Calibrating. Consult the Blockware to determine the Block Number of
the
TOUT
function that drives the actuator being calibrated. Use S/M mode to move the actuator during this
