ML7984B
VALVE ACTUATOR
The ML7984B is a self-contained, self-adjusting,
linear motorized linkage that mounts directly
onto V5011 two-way or V5013 three-way valves
and provides up to 19 mm (3/4") of linear travel
(stem lift). For use with a Pulse Width Modulating
or alternately a 2-10Vdc analog signal controller.
• Allows the use of one common transformer power
supply for multiple actuators and controllers
• Multipoise mounting
• Strong valve seat closing force 710 Newton (160
lbs.)
• Field configurable DIP switches for 5 PMW modes
and 2-10Vdc signal inputs.
• Compact size for easy installation in confined areas
• Field configurable DIP switches for Direct / Reverse
action
• Electronic current sensing provides internal
protection and positive full closing force
• One device for either Vac or Vdc power supply
application
• Field-addable auxiliary switches available
• Compatible with 3 -wire system (one common wire
for both signal & power inputs)
• For 1/2" to 3" V5011 / V5013F &G valves
• Self-contained, motorized valve linkage.
CONTENTS
• Linkage self-adjusts to valve stroke of up to 19 mm (3/4")
Specifications.......................................... 2
Order information................................... 2
Installation.............................................. 3
Wiring Schematics.................................. 5
Operation and Checkout......................... 6
PCY • 2-96 • © Honeywell Ltd. 1996 • Printed in Canada * Form number 95C-10808
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ML7984B
SPECIFICATIONS •INSTALLATION
FIG. 1 -- DIMENSIONS OF ML7984 VALVE ACTUATOR IN MM (INCHES).
Installation
Mounting:
1.Ensure that the valve body is installed correctly, that is, the
arrow points in the direction of the flow.
2. Although the actuator can be mounted in any position, it is
preferable that the ML7984 is mounted above the valve body.
This will minimize the risk of damage to the ML7984 in the
event of condensation or a valve gland leak.
3. Remove the stem button (Fig. 3) from the valve stem.
4. Slide the position indicator (plastic disk or rubber O-ring)
over the valve stem. (See inset, Fig. 3) Indicator will self-
align to the marking on the yoke after one complete operating
cycle.
Assembly of ML7984 to the valve:
1. The drive shaft of the ML7984 has a threaded hole to link
with the valve stem. Slide the yoke over the valve bonnet
(Fig. 4)
2. Thread the ML7984 drive shaft onto the valve stem all the
way, until it is completely attached (with no threads
showing), by turning the valve actuator in a clockwise
direction, as viewed from above (depending on the valve
models, use a pin or wrench to keep valve stem from turning).
Note that the valve actuator is shipped with drive shaft in the
mid-position.
FIG.2 -- MINIMUM MOUNTING CLEARANCE.
!
CAUTION
3. Care should be exercised when using the TOOLS on the
1. Installer must be a trained service technician.
2. DO NOT electrically operate
before assembly to the valve bec
not apparent to the installer may occur.
valve stem during tightening. (Fig.4) DO NOT damage the
threads or other parts of the stem.
4. Orient the conduit hole to the most desirable direction, then
tighten the LOCKNUTS on the U-bolt.
3
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ML7984B
INSTALLATION
FIG.3 -- PREPARATION FOR VALVE ASSEMBLY.
FIG. 4 -- ASSEMBLY OF ML7984 TO VALVE.
5. Remove the plastic cover from the ML7984 by loosening
the two screws located on the top (Note: These screws are
captive. Rotate three complete revolutions to remove cover ).
Drop either slot headed or Allen hex type of set screw (both
are included in the plastic bag ) into the top of the shaft,
slot/hex side up.
6. With a 5 mm (3/16") Slotted screwdriver or 1/8"x 6" Allen
wrench (included in the plastic bag), tighten the set screw to
lock valve stem in place (Fig. 6).
! WARNING
For proper valve operation, valve stem must
be threaded into the actuator all the way
(with no threads showing) and locked in
place with the set screw provided.
FIG. 6. -- LOCKING ML7984 DRIVE SHAFT TO VALVE
STEM
FIG. 5 -- U-BOLT ASSEMBLY.
4
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ML7984B
WIRING
4
SIGNAL
SOURCE
3
2
ML7984B
1
+
R
T6
T5
2-10 Vdc
L1
L2
W
B
24 Vac
PWM
C
OR
+
T6
T5
28 Vdc
-
Allow 0.5 amps maximum for each device. Actuators and controller can share same transformer providing the
VA rating of the transformer is not exceeded and proper phasing is observed.
1
2
"T5" and "W" terminals are factory connected internally. Device is compatible with the 3-wire control system.
Use configuration DIP switches to select device functions: Direct acting function ( actuator stem moves upwards
with signal increases ) or Reverse acting function ( actuator stem moves downwards with signal increases ).
3
4
Use either one controller only
MODE
DIP SWITCH
on
PWM: min. 0.1 sec + 0.01 sec increments (max. 2.65 sec )
PWM: min. 0.1 sec + 0.02 sec increments (max. 5.20 sec )
PWM: min. 0.1 sec + 0.05 sec increments (max. 12.85 sec )
off
1
3
2
on
off
on
off
on
off
4
1
1
2
2
3
3
Direct
Acting
on
off
on
off
on
PWM: min. 0.1 sec + 0.10 sec increments (max. 25.6 sec )
1
1
1
3
3
3
2
2
2
off
4
PWM: min. 0.59 sec + 0.00918 sec increments (max. 2.93 sec ) NOVAR
Reverse
Acting
on
Analog: 2-10 Vdc
off
Configuration DIP switches
NOTE:
located adjacent to the input
terminal block
Turn power off before setting the DIP switches.
Fig. 7 Wiring for ML7984B actuators
5
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ML7984B
OPERATION AND CHECKOUT
Operation and checkout
Operation:
The recommended valve actuator power source is a class 2,
24V transformer or 28Vdc across terminals T5 &T6 (See
Fig.7). The internal circuitry provides dc power for the
electronic sensing and drive motor circuits. The sensing
circuits respond to the signal across the input terminals
based on the configuration DIP switches setting.
CAUTION:
1. Disconnect power supply before beginning installation to
prevent electrical shock and equipment damage.
2. All wiring must comply with applicable local electrical
codes, ordinances and regulations.
3. Make certain that the voltage and frequency of the power
supply correspond to the rating of the device.
4. DO NOT electrically operate the ML7984 before
assembly to the valve because damage not apparent to the
installer may occur.
!
At the end of the valve stroke, the actuator continues to
drive and gradually develops the necessary force for
positive valve close-off. The actuator motor stops
automatically when the motor current
predetermined current & force level.
reaches the
PWM mode:
The ML7984B is controlled by an intermittent voltage pulse
whose width varies in proportion to the desired actuator
position. This called pulse width modulation (PWM). The
PWM signal has two parts: a fixed pulse of a set width to
indicate a signal presence (e.g. 0.1 s) and a varible width
portion incremented in proportional to the signal percentage.
There are 255 increments available (e.g. 0.01 s). Thus, the
pulse width will be the minimum width plus the number of
increments times the incremental value (e.g. stroke mid
position is: 0.1s +128 x 0.01s = 1.38 s). The ML7984B
supports 5 different PMW timebased modes.
Checkout:
1. Make sure the valve stem is completely screwed into the
actuator drive shaft with no threads showing.
2. Make sure the valve stem is locked in place with the set
screw.
3. Make sure the Configuration DIP switches are set
correctly.
4. With 24Vac or 28Vdc power source connected to T5 &
T6, actuator operation can be verified by connecting
appropriate control signal (PWM or 2-10Vdc) from
controller to the signal input terminals (Fig. 7).
For direct acting: A modulating action can be obtained
simply by increasing the control signal width or level. The
actuator will travel from a fully closed position (Stem down)
to a fully open position ( Stem up ). For 2-10Vdc mode,
actuator defaults to closed position on signal failure.
For reverse acting: Decreasing controller signal width or
level will drive actuator from fully closed (Stem down) to a
fully open position (Stem up). For 2-10Vdc mode, actuator
defaults to open position on signal failure.
2-10 Vdc mode:
Control signal between signal input terminals is compared
to similar voltage across the actuator feedback
potentiometer. When these voltages are equal, the drive
motor and drive shaft are stationary.
As long as the value of controlled medium remains at the
controller setpoint, the circuit is in balance, and the actuator
does not run. When the value of the controlled medium
changes, the controller output voltage is changed causing
reference voltages in the circuit to be out of balance. As the
actuator moves in the direction to correct the medium
change, the feedback potentiometer also moves to rebalance
the circuit, and stop the actuator.
5. Operate the system (valve, actuator and controller) for
several cycles to ensure proper installation.
6. When checkout is completed, return the controller to the
desired setting.
GENERAL NOTE:
1. For correct valve operation, the ML7984 must be field
configured with the DIP switches which are located beside
the terminal block, see wiring diagram for details. Turn
power off before setting the DIP switches .
NOTE: Device will ignore any input changes until it has
2. There is a short delay in actuator response upon every
signal change. It is to screen any unwanted incoming signals.
3. For proper operation, voltage on the T5 & T6 must not
be less than 22Vac or 24Vdc during running or force
generating stages.
completed its repositioning relative to the initial signal input.
Home and Building Control
Honeywell Limited/Limitée
155 Gordon Baker Road
North York, Ontario
Home and Building Control
Honeywell Inc.
1985 Douglas Drive North
Golden Valley, Minnesota 55422
Helping You Control Your World
Canada M2H 3N7
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