Hamilton Sundstrand Company ACT2000 - Manual (Page 40)

34 ACT2000 USER GUIDE
The ACT2000 will then slowly increase the motor current to the ACT2000
until the current level corresponding to the Maximum Homing Force has
been applied. This Maximum Homing Force is also specified in the Set
Up parameters and has a default value of 500 lbf. When the pre-
determined motor current limit is reached, the ACT2000 defines this
actuator position as Home. The system will then transition to the Holding
Motor Current State. See the flow chart in Figure 3-1 for an overview of
this process.
The DEMAND current determines subsequent positioning of the actuator
within its span once the Home position has been established
See Section 3.8 for additional information about Set-Up parameters.
3.3 Holding Motor Current State
In the Holding Motor Current state, the actuator applies a constant
Holding Force. This feature allows the Home position to thermally expand
or contract without damaging the ACT2000. This Holding Force is
specified in the Set Up parameters and has a default value of 500 lbf.
The system is in the Holding Motor Current state immediately after
Homing. The system will also move into this state when the DEMAND
signal is > 2mA and < 4.1mA. See the flow chart in Figure 3-1.
3.4 Moving to Stop Position
The Stop position is a fail-safe position that may be set anywhere
between Home (zero position) and maximum span. The default value for
Stop position is 0.1 inches, as defined in the Set-Up parameters.
The actuator will move to the Stop position if the DEMAND signal is
≤ 2 mA (signal loss) at any time after the actuator has completed Homing.
It will also move to the Stop position if the RUN command is removed
during any of the running modes. See the flow chart in Figure 3-1.