80-4280-10, Rev. 4
11
HANDSWITCH
Handswitch operation allows local electric
control at the damper. In the STOP positions,
the motor is blocked from running. In the CW or
CCW positions, the motor runs to move the output
shaft in the
corresponding
direction.
When moving
the output
shaft using the
H a n d s w i t c h ,
the motor will
stop when the
over-travel limit
switches are actuated.
The Handswitch is designed so that a Demand
signal can operate the actuator only when the
Handswitch is in the AUTO position.
AUTOMATIC MODE
When the Handswitch is placed in the AUTO
position, the actuator is in automatic mode and
is ready for remote electrical control. When the
actuator is in AUTO it responds to a 4-20 mA
control signal (also called the Demand signal or
setpoint) applied to terminals 14(-) and 15 (+). The
electronics (DCM-2) will compare the control signal
with the current output shaft position to determine if
there is a difference. When the electronics detect
a difference in Demand and position (called error),
the motor will run and position the output shaft until
the position matches the Demand.
OVERRIDE
Override operation can be used as a means
of emergency operation or an alternate control
method if 4-20 mA analog signalling is not
available. PAT controls can be adapted by using
external relays (solid state) to interface with the
overrides.
Analog signal operation may be overridden
by using relay logic input signals on the control
override input terminals. CW (19), CCW (20) ,
and STOP (21) terminals require connection to
a common (COM) terminal (18) to perform the
override as shown in the figure below.
STOP
CCW
CW
COM
TERMINAL
CONNECTIONS
EXTERNAL
RELAY CONTACTS*
* Relays must be capable of syncing at
least 5 mA of DC current
Handwheel
MODES OF OPERATION
The Group 22 electronic actuators have four
basic modes of operation as follows:
1. Handwheel operation -
local mechanical
control
2. Handswitch operation -
local electrical
control
3. Automatic mode
- remote electrical control
4. Override mode
- remote electrical control
Any or all of these modes can be used to test
basic operation of your actuator during startup.
HANDWHEEL
Every Group 22 Beck actuator is furnished with
a Handwheel to permit manual operation of the
actuator with or without the supply power applied.
Its solid construction design includes no spokes
or projections, and turns at a safe, slow speed.
The Handwheel is coupled directly to the motor
shaft at the rear of the control motor housing and
rotates when the motor runs.
Handwheel operation can be used at any time,
but is especially useful during initial installation or
when power is not available. If power is available,
the Handswitch must be in the “STOP” position
before manually operating the Handwheel.
GENERAL OPERATION INFORMATION
