PA Industries Magnum Servo Roll Feed SRF-M12/18/24/32/36/48 - Operation Manual - Manual (Page 6)

ULTRA MAGNUM SERVO ROLL FEED 5 /23/2003
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2.5 PLS OPERATION (OPTIONAL)
The PLS, Programmable Limit Switch consists of an intelligent encoder and the cable that connects the encoder to
the servo drive. The encoder is mounted on the press and its shaft is coupled or belted to the crankshaft with a one to
one (1:1) ratio. On every power-up, the encoder turns into the intelligent mode (for approximately 10 msec) to read
its actual position and store it in the servo drive.
The encoder then turns into the incremental mode, sending the count signals to the servo drive proportionally to the
angle of the move (1024 counts per revolution). The servo drive software, having the start point position of the
encoder shaft, constantly calculates (updates) its current position. The position of the press crankshaft is determined
through the offset parameter, which is the position of the encoder shaft when the press is in its 0 degree position
(TDC).
Thus, at every point of the stroke, the servo drive knows where the crankshaft is. The servo drive controls six cams
simultaneously, turning them on and off accordingly to the cam settings.
Since the PLS encoder is connected directly to the servo drive, there is no need to wire connections for the Feed Cam
and the Reset Cam outputs. These outputs are software type outputs.
The rest of the cam outputs are hardware type and require wiring of output relays to the desired mechanisms, such as a
pilot release solenoid, parts blow-off, tool lubricator, etc. The cam settings (On/Off angles) are set through the
operator terminal. They are part of the tool settings.
NOTE: All PLS outputs are active as soon as SRF power is turned on.
2.6 STRIP ENCODER-OPERATION (OPTIONAL)
The Strip Encoder assembly consists of:
a. 300mm diameter knurled measuring wheel
b. 10,000 pulses per revolution encoder
c. Air valve with manual actuator
d. Air cylinder slide
e. Magnetic sensor
The encoder measuring wheel is coupled to the encoder and both are mounted on the slide. The slide can be moved up
and down by applying air pressure (80-100 PSI) to the air cylinder. The magnetic sensor is used to indicate the
up/down position of the measuring wheel.
The encoder output results in 40,000 pulses (counts) per revolution for a final resolution of 3386 counts per inch of
linear strip movement.
While the measuring wheel is in its up position, the servo roll feed acts as if there is no strip encoder attached to it, and
all of the SETUP parameters associated with a strip
encoder operation are inactive.
The Strip Encoder may be used to control or to check the position of the material strip.
The P/A Industries® servo roll feed with optional Strip Encoder comes standard with the ability to function in one of
the two modes.
1. CONTROL MODE
In this mode the position control of the material motion is done through Strip Encoder feedback. The velocity control
is based on data coming from both, Strip Encoder and Motor Mounted Encoder.
This mode provides relatively slower speed performance, due to the increase in computation of the velocity control
algorithm.