Bimba PCS - Manual (Page 8)

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The following formula will translate the voltage reading into the Decel Range.
DR = 0.01485 * V * t
Where:
DR = decel range
V = voltage reading from the PCS
t = full scale travel of the actuator (Note: for PTF rotary actuators
with total rotation less than 180º, always make t = 180)
Example
1: If the Decel Range is set to 5 volts for an 8 inch stroke cylinder, then
deceleration will occur for 0.60 inches (0.0149 * 5 * 8).
Example 2: If the Decel Range is set to 5 volts for a 180º rotary actuator, then
deceleration will occur for 13.4º (0.0149 * 5 * 180).
CURRENT POSITION
Current Position is a 0 to 10 volt output signal that mirrors the feedback signal
from the actuator, fully scalable with the Zero and Span adjustments. In other
words, its output will always be 0 to 10 volts no matter how Zero and Span are
adjusted. It can be used to monitor the motion of the actuator and the output may
be sent to a calibrated display.
AT POSITION (@ POS)
At Position is a digital output signal that is normally open and switches to ground
when the actuator is within the Deadband zone. This signal is useful for utilizing a
PLC I/O card to receive a signal indicating that the actuator is within the
Deadband zone, potentially eliminating the need for an analog input card.
Be cautious when utilizing the @ POS signal. If there is overshoot in the
application, the actuator may momentarily go through the Deadband
Zone, causing the @ POS signal to momentarily transition back open,
before finally stopping in the Deadband Zone.
REPEATABILITY AND STABILITY
It is important to understand the difference between repeatability and stability. A
system is considered repeatable if it comes to a stop inside the deadband zone. A
system is considered stable if it comes to a stop in the deadband zone time after
time with no overshoot. There are different degrees of instability. The first is a
system that approaches the commanded position and overshoots it just a little and
has to reverse itself before settling to a stop in the deadband zone. This level of
instability may be acceptable in many applications. The worst type of instability is
oscillation around the deadband zone, never settling to a stop. This level of
instability must always be resolved.
MOVEMENT DIRECTIONS
Movements of the actuator may be described as “Increasing” or “Decreasing.” An
“Increasing” move is one that moves toward the Full Scale Position. A
“Decreasing” move is one that moves toward the Zero position.