Specifications

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MX Protection, Control and Monitoring Features FCD LMENTB2300-01 – 07/08
cycle to free the valve. If this is unsuccessful, further electrical operation is prevented and the monitor
relay is signaled.
Instantaneous Reversal Protection
The control logic incorporates a brief time delay (from 0.5 to 1.0 seconds) between motor reversals.
This reduces motor current surges and prolongs the life of the contactor. Note: It is not necessary to
switch to STOP before reversing the actuator.
Motor Thermal Protection
The motor is protected against overheating by a thermistor embedded in the motor windings. Standard
thermistor threshold is set for 120˚C (Class B). Options are available for other classifications.
2.3 Optional Control Features
Modutronic
The Modutronic controller will alter valve position in proportion to an analog command signal. It
includes an automatic pulsing mode to reduce overshoot at the set point.
The following parameters may be easily set during the configuration of the unit:
Proportional Band range from 0.1% to 100% (15% = default) •
Dead Band range from ± 0.1% to 50% (2% = default)•
Polarity 20 mA = OPEN (default) or 20 mA = CLOSE•
Action on loss of command signal OPEN, CLOSE, STOP (CLOSE = default), or Move-to a previously •
configured position
Delay after stop 0–60 seconds (0 = default)•
Command Signal•
4–20 mA•
Input impedance - 150 ohms•
Repeatability – The Modutronic is repeatable to within ±0.5%. Repeatability is defined as encoder
feedback position versus position command. Overall valve and actuator system accuracy depends
on many factors, including actuator gearing backlash and valve/actuator coupling tolerance, and
therefore cannot be defined by this document.
Extrema Mode – If the command signal represents a position of 0–2% OPEN (nominal 4.00–4.32
mA) or 98–100% OPEN (nominal 19.68–20.00 mA), then the MX will move the valve directly to that
position, without pulsing.
Positioning Frequency – The standard frequency is suitable for a rate of 600 starts/hour for short
periods, typical of process start-up. Typical process control of ≤ 100 starts/hour. An optional solid-
state motor reverser (SSMR) is available for process rates > 600–1200 starts/hour.
Analog Position Transmitter (APT)
The APT is an internally powered, non-contacting valve position transmitter. The isolated output
signal is proportional to the position of the valve and is available as 4–20 mA and/or 0-20 mA, 0-10
VDC, 2-10 VDC, 0-5 VDC, or 1-5 VDC.
The user may select the minimum signal to represent either the fully OPEN or the fully CLOSE posi-
tion of the valve during the setup procedure.