Multiplier Signals; Multiplier Board Setup; Oscilloscope; Equipment And Tools Required - Aerotech MXH Series Hardware Manual

Introduction

1.2. Multiplier Signals

The multiplier board accepts 1 V peak-to-peak voltage input signals. The outputs are square wave, RS-422
TTL compatible signals. The input marker signal is expected to be active high and located at the 255° point of
the 360° electrical cycle. The plots illustrated in
sine, and marker).
TP10 - COSINE
Approx. Ref 2.5 V
0V
TP9 - SINE
Approx. Ref 2.5 V
0V
TP6 - MARKER

1.3. Multiplier Board Setup

The MXH Multiplier is designed to work with perfectly sinusoidal signals with no DC bias (offset). The actual
magnitude of the sine and cosine signals is not as important as the value of one signal relative to the other.
The MXH multiplier is a "ratio-metric" device, which means that the sine and cosine signals should be
adjusted for equal peak amplitudes. Any gain imbalance between the sine and cosine signals will result in
cyclic interpolation errors in the MXH output.
Any DC bias (offset) in sine or cosine will also cause cyclic interpolation errors in the multiplied output.
The gain and DC bias can be adjusted for each signal on the MXH multiplier circuit board.

1.3.1. Oscilloscope

Generally, systems operating at less than optimum performance due to interpolation errors will exhibit the
following symptoms:
1. A constant whining noise can be heard when running at low speeds.
2. At high speeds, a chirping noise can be heard when the table is accelerating and decelerating.
3. Using Aerotech's application software as a diagnostic tool, a harmonic or a sub-harmonic of the
fundamental encoder frequency may be seen in the position error or velocity error plots of the axis
scope window.

1.3.2. Equipment and Tools Required

1. A two-channel oscilloscope capable of being isolated from ground and displaying a Lissajou pattern (X,
Y) of the sine and cosine encoder signals
2. Small slotted tip screwdriver or adjustment tool.
N O T E : The amplified signals can not exceed 4V peak-to-peak or a loss of accuracy occurs.
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Figure 1-3
1.9V
3.8V
pk-pk
1.9V
1.9V
3.8V
pk-pk
1.9V
INPUT SIGNALS
(After amplification on the MX board)
Figure 1-3: Plot of Input and Output Signals
Chapter 1
MXH Multiplier Option Manual
show typical input and output signals (cosine,
OUTPUT SIGNALS
COSINE
SINE
MARKER
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