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4 Gantry System 4.2 Reference Run 38 Technical Training FSE SIPLACE TX-Series 01/2018 Reaching the HW end position, change of driving direction and finding the zero pulse After the commutation search, the motor is in an …

4 Gantry System

4.2 Reference Run

Technical Training FSE SIPLACE TX-Series 01/2018 37

Reference Run Workflow

Reference Run detailed Workflow

Preconditions: Axis reference run must be successfully completed for the relevant placement

heads.

Commutation position search for 3 phases AC-drives on gantry during initial reference run:

1. Two motor phases are switched by the MGCU.

2. The 3-phase AC motor moves to the next suitable magnetic position.

3. Two other motor phases are switched by the power supply and the axis moves further.

4. These switching steps are repeated multiple times.

5. The axis reference run is continued with a reference position search for the position measur-

ing system.

4 Gantry System

4.2 Reference Run

38 Technical Training FSE SIPLACE TX-Series 01/2018

Reaching the HW end position, change of driving direction and finding the zero

pulse

After the commutation search, the motor is in an undefined position for the control system.

1. Referencing with bumper recognition (hardware end stops), the axis moves successively

against the bumpers. This is done using fixed target values set by the axis controller, these

are increasingly closer to the mechanical end stop.

2. After a some time, the axis reaches a state in which the set target position is no longer

reached (actual position ≠ target position), the axis is at the hardware end stop (bumper).

3. After reaching a certain motor current (approx.10ms later) the direction of travel is reversed

and the axis searches for the zero pulse within a specified range. The motor is now in posi-

tion control.

Zero pulse

Bumper

No searching area for the zero pulse configurable

Area to check the right zero pulse

Searching area for zero pulse configurable

4. The search for a zero pulse is prohibited within a certain distance from the bumper (approx.

25mm).

5. After moving out of this prohibited area, the search begins. If the zero pulse is found in this

area, further pulses will be searched for in an area of approx. 2.5 mm. If only one zero pulse

is found, an end position message is issued and the reference run is completed.

6. In the event of a fault (multiple zero pulses or no zero pulses in the defined area) the axis will

stop and an error message will be issued.

7. The axes are now in a defined position. After finding and checking the zero pulse, the zero

point correction is loaded.

8. The reference run for the main axes has now been completed.

9. The vacuum and height reference runs will begin.

The reference run for the main axes is started simultaneously at all gantries.

TX micron gantry differences

●

X/Y glass scale thermal stable Robax-scales (glass-ceramic composite) for gantry system

with highest resolution of 10nm.

●

Encoder interpolate 20um

– X-Encoder TXm MS30

– Y-Encoder TXm MS30

●

Two sensor modules mounted on the X-Axis which convert the analog X and Y track signals

in to digital signals.

4 Gantry System

4.3 Calibration after Repair and Adjustment

Technical Training FSE SIPLACE TX-Series 01/2018 39

4.3 Calibration after Repair and Adjustment

4.3.1 Explanation of main Gantry Calibrations

Zero point offset (machine Zero Point Correction)

The machine ZPC (station point for each gantry) is used as point of reference for the X/Y Axis to

the machine coordinate system. Thus the axes know their current positions in the machine. The

PCB camera moves towards this machine zero point (fiducial). Then the X/Y directions are meas-

ured. The resulting offset is taken into account in the fixed zero point correction of the X/Y Axis.

Travel range

The axis concerned moves as far as possible towards the minimum or maximum position and the

limit is set.

System identification

Checks the controls parameters of the X/Y Axis to ensure reliable control of the axis movement.

The procedure should be repeated if the machine has been moved or if gantry conversion has

been done.

X Axis parametrization

Optimizes the X Axis control parameters.

Board camera (PCB camera)

Determines the calibration factors, the relation of the camera pixel size to the resolution of the

machine measurement system (X, Y) and the mounting angle of the CCD sensor in the PCB cam-

era.