PVA PVA2000 - Calibration Procedures; Standard Needle Calibration; Operator Defined Needle Calibration; Sensor Defined Needle Calibration

Operation and Maintenance Manual Rev M(ii) 4/03
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Calibration Procedures
The workcell has one of three calibration methods: Standard, Operator Defined and Sensor Defined. If a
Sensor Defined or Operator Defined method is installed on the workcell, the machine may or may not
automatically enter its particular calibration mode following the homing sequence depending on the
application the workcell was set up for. See page 24 for particulars on operating the workcell during a
calibration sequence.
Standard Needle Calibration
The simplest calibration procedure requires the operator to visually inspect the position of a needle with
respect to a calibration point (such as cross-hairs). If the needle is not directly above the point, the operator
must physically reposition the needle so it is above the calibration point.
Operator Defined Needle Calibration
This method is dependent upon the operator utilizing the trackball to redefine the coordinate system
according to the positioning of a specific needle or dispense head. This process is optional. If the specific
needle is located in the desired position this process can be skipped.
The calibration routine automatically runs when the machine is powered on or if the controller is reset. The
head moves to a calibration point (specified in the main program). When at the calibration position the
operator has control of the axes. Using the trackball, the position of the needle tip can be redefined in
reference to a calibration point (such as cross-hairs). This process can also be run manually through the
CAL function key if a needle needs to be replaced for any reason during operation.
Sensor Defined Needle Calibration
This method focuses around the NCU (Needle Calibration Unit). The calibration sequence redefines the
coordinate system according to the positioning of a specific needle or dispense head. Limitations may arise
with a multiple head workcell utilizing two or more dispense heads in the same path program.
The NCU is referenced from the home position on the gantry. The start positions for each head to enter the
NCU are referenced from the cross-hair mark on the top of the NCU. The coordinates are defined for each
head using reflective sensors in the NCU. Z is always calibrated first in a downward motion into the Z
sensor. The X and Y coordinates are then calibrated from this position in reference to the positioning of the
NCU in the work area. The needle moves into the next sensor (X or Y) finding the first coordinate, then
moves to the opposite side of the sensor and finds a second coordinate. The calibration routine then
calculates the average of the first and second coordinates and redefines the new position accordingly. This
sequence is repeated for the remaining axis.
Shutdown Procedure
If the machine is in cycle, wait for the cycle to finish and then return to the Cycle Stop mode. If the
machine is in any other mode, the operator should return to Cycle Stop.
1) Press the EMERGENCY STOP button.
2) Turn off power to the system. Rotate the main disconnect switch to the “0” position (Rocker switch on
PVA250™ models).
3) Clean any excess material from the tips of the needles.
4) Remove spray cap(s), wipe tip of needle/seat as well, clean cap thoroughly.
5) If the system will be down for an extended period of time, it is recommended to turn off the air to the
machine. The red lockout valve at the rear of the machine can be used for this (not applicable on
PVA250™ model).