M2CP Digital Futronic User Manual
84829 Rev F
EIM Company, Inc 13840 Pike Road Missouri City, TX 77489 (281) 499-1561 Page 6
D
EFINITIONS
Command = 4-20mA analog input position command signal generated by remote control equipment.
Same as position command setpoint. Zero and Full-scale calibrated by user.
Position = 0-5V valve position analog input signal generated by Hall-effect Position Sensor (HPS). Zero
and Full-scale automatically calibrated by controller based on LSC and LSO valve travel limit switches.
Feedback = 4-20mA analog output signal for feedback of valve position to remote control equipment.
Zero and Full-scale calibrated by user.
Invert = Inverted calibration of 4-20mA command where close position = 20mA, and open position =
4mA. Feedback is also inverted.
Deadband = Allowable error tolerance to keep valve stopped, i.e. do not turn on motor control outputs.
Deadband can be configured by the user as the defined default values or double the default values.
Deadband has a beginning default value based on selected operating mode (motor starter type) and then
controller automatically adjusts the deadband to obtain the best accuracy.
Default deadband based on motor starter type:
Futronic II = +/-1.0% deadband
Futronic III = +/-0.25% deadband
Futronic IV = +/-0.50% deadband
Error = Difference between Command and Position.
Error=Command-Position
If not Invert and Error=Positive then open valve
If not Invert and Error=Negative then close valve
If Invert and Error = Positive then close valve
If Invert and Error= Negative then open valve
Nonlinearity = Difference between analog input and analog output at current valve position over the full
valve operating range.
Close Coast = Difference between Position when the motor is turned off and Position when the valve
stops moving in the close direction. Coast is caused by both inertia of the motor and latency of Position
update due to analog input filtering. The controller measures close coast to automatically tune control for
maximum accuracy.
Open Coast = Difference between Position when the motor is turned off and Position when the valve
stops moving in the open direction. The controller measures open coast to automatically tune control for
maximum accuracy.
Modulation Delay = Time between when the motor is turned off until the motor can be started again. This
delay prevents excessive number of starts of the motor, preventing overheating the motor and premature
burnout of the reversing contactor. Modulation delay also prevents valve plugging when the actuator
reverses direction. If a three phase motor is used, the delay time is 2 seconds or 1800 starts per hour. If a
single phase, capacitor start, AC motor is used, then the delay is 12 seconds or 300 starts per hour. The
delay between motor control pulses while the valve is being jogged to position is automatically reduced to
one second.
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