Flowserve DRC-17 - Manual (Page 19)

WCAIM2058 DataFlo Digital Electronic Remote Controller DRC17 19
4.6.4 DRC Programmable Parameter Definitions
Parameter Display Definition
Security Code Sec Code The security code is used to prevent unauthorized access to other modes. A security
code of 0000 disables security checking. All other code numbers will require an
operator to enter the correct code to change to other modes.
Unit Address Unit Adr Communications address.
Output Current Range Curr Rng Defines the range of the position feedback output current module.
Proportional Term P-term Coefficient used in computing the proportional part of the PID algorithm. This term
determines the effect of the (process - setpoint) error. The higher the proportional
term, the greater the correction or valve movement for a given error.
Integral Term I-term Coefficient used in computing the integral part of the PID algorithm. This term
determines the effect of a prolonged difference (process - setpoint) error. The higher
the integral term, the greater the correction or valve movement with a prolonged
error condition.
Derivative Term D-term Coefficient used in computing the derivative part of the PID algorithm. This term
determines the effect of a change in the present process value and the process value
8 seconds ago. This change is important in controlling systems that respond quickly
or that have a significant lag. The effect of the rate of change can be amplified or
ignored using the derivative term.
Motor Cycle Interval Cyc Intr The time interval at which the motor will make a correction (e.g., once every 1.5 sec).
Filter Time Flt Time The length of time over which process readings are averaged. This time should never
be greater than the motor cycle interval.
Backlash Time Bkl Time The extra amount of time the motor will run when the direction is reversed to
compensate for gear backlash in the gear drive train.
Torque Time Trq Time The extra amount of time the motor will run to overcome the torque needed to move
the valve. In valves with a high torque, this parameter is important to overcome the
imposed stress on the gears when they try to move the shaft.
Deadband Dead Bnd This parameter is used to prevent oscillations about a setpoint because of small
fluctuations in either the setpoint signal or the feedback process signal. It is an area
in which the process is in control and the valve will not move.
Action Action Describes which direction the valve will move to correct the process. RISE means
that if the process is greater than the setpoint, the actuator shaft will travel in the CW
direction. FALL means that if the process is greater than the setpoint, the actuator
shaft will travel in the CCW direction.
Cycle Interval Reset Cyc Res Determines whether to reset the Motor Cycle Interval timer when the process is
within the deadband.
Process Low Alarm Value PrLo Alr Process value below which an alarm condition will be issued.
Process High Alarm Value PrHi Alr Process value above which an alarm condition will be issued.
Invalid Reading Position SigErPos Valve position to go to if an invalid setpoint or process value is read. If the DRC
should attempt to keep controlling in the event of an invalid reading, set this
parameter to IGNORE. It can also be set to the value of HOLD to hold the position.
Invalid Shaft Position Reading Action FBErrAct Valve movement action to perform if an invalid shaft position is read. The valve can
be set to drive full CW (Full CW), drive full CCW (Full CCW), HOLD its position, or
IGNORE to keep controlling in the event of an invalid reading.
Flow Control
Worcester Actuation Systems