EXPLAINATION OF THE DIFFERENT FUNCTION OPTIONS
Power to open, power to close: Stays put on mains power failure.
On receipt of a connuous power signal, the motor runs and via a planetary gearbox system,
rotates the output sha. The motor is stopped by internal cams, ed to the output sha, strik-
ing micro-switches which cuts power to the motor. When a subsequent connuous signal is re-
ceived, the motor will turn in the opposite direcon, reversing the direcon of rotaon of the
output sha. The actuator can be jog controlled by switching the power on to start and o to
stop.
Failsafe Function: Power open, power close, fails to pre-set position on
power failure
Under normal operaon the EA218 failsafe electric actuator operates as an on-o actuator as
above. Whilst power is applied, an internal industrial rechargeable baery is trickle charged to
ensure it is fully charged. In the event of external power failure, the power source is switched
from external to internal and baery power is used to send the actuator to the pre-set 'safe'
posion, if not already in that posion. Standard fail posion is closed (fail closed or normally
closed) but fail open (normally open) can be set. On resumpon of external power, the actuator
will move relave to the command signal being applied at the me power is restored. This safety
system is called BSR (Baery 'Spring Return'). The BSR is a plug and play kit that can either be
supplied installed and tested by us, or supplied as a simple to install and user friendly retro-t kit.
Modulating Function: Movement of the actuator is proportional to an
input signal via a digital positioner. Stays put on loss of external power.
The is a self-calibrang and auto-adjusng Digital Posioning System supplied as a retro-t opon
to the range of reversible electric actuators to produce modulang funconality. The self-
calibrang feature senses the motor stop closed posion and sets the span from this posion,
and then auto-calibrates the steps between open and closed for either 4-20mA or 0-10VDC con-
trol signals. Hunng has been virtually eliminated in the DPS and as soon as the actuator arrives
at the required posion relave to the input signal, it stops. On receipt of a control input signal
the actuator will move to the posion relave to the input signal eg: using a 4-20mA signal, 4mA
input signal closes the actuator, a 12mA signal sets the actuator at 45° and a 20mA signal opens
the actuator. Each subsequent change of input signal will cause a corresponding change to the
actuator posion. This funconality can be reversed (reverse acng) if required. An output signal
in the same form as the input signal is supplied as standard. In the case of control signal failure,
the actuator will move to the closed posion (or open if congured reverse acng). In the case of
external power failure, the actuator will stay in the posion it saw at the moment of power inter-
rupon, and will move to the signal it sees on resumpon of external power.
Failsafe Modulating Function: Fails to pre-determined safe position on
loss of control signal or on loss of external power
The EA218 Modulang actuator fails to safe posion on loss of power. By installing both the BSR
and DPS funcon conversion kits, the EA218 can provide failsafe modulang funcon in all mod-
els.
EA218 ON-OFF ACTUATOR
DPS can be set to FAIL FREEZE
on loss of control signal.
Can be set to fail open, or fail closed
EA218 FAILSAFE ACTUATOR
EA218 MODULATING ACTUATOR
EA218 FAILSAFE MODULATING
ELECTRIC ACTUATOR
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