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User Manual
E727T0005, valid for E-727
BRO, 2019-06-28
Physik Instrumente (PI) GmbH & Co. KG, Auf der Roemerstrasse 1, 76228 Karlsruhe, Germany
Page 110 / 240
Phone +49 721 4846-0, Fax +49 721 4846-1019, Email
Example 2: Use Generator Level Trigger mode to switch the digital output line to a certain level for
a certain range of the waveform.
Command String to Send
Action Performed
WAV 2 X SIN_P 2000 20 10 2000 0 1000 Define a sine waveform for Wave Table 2, the
segment length and hence the number of points in
the wave table is 2000
CTO 1 3 4
The digital output line OUT1 is set to "Generator Level
Trigger" mode.
TWS 1 1 3 1 750 2 1 1150 3
For all waveform points from point 1 to point 749, the
output line is set low. At point 750, there is a rising
edge on the output line. Therefore, the output line is
set high from point 751 to point 1149. At point 1150,
there is a falling edge on the output line, and for all
subsequent points the line will therefore be set low.
WSL 1 2
Connect Wave Generator 1 (Axis 1) to Wave Table 2
WGO 1 1
Start output of Wave Generator 1 immediately
(synchronized by servo cycle). Now the trigger output
action will take place as specified.
WGO 1 0
Stop output of Wave Generator 1 and hence also the
trigger output.
INFORMATION
If a phase shift between the trigger output and the actual position is observed when the wave
generator is running with the "Use DDL" or "Use and reinitialize DDL" options (actual position
measured with external device is ahead of the trigger signal), check the cut-off-frequency f
g
of the
IIR low-pass filter used for digital filtering and increase it to shorten the duration of the digital
filtering. See below for details.
The duration of the signal processing for an internal sensor results from two portions:
Duration of the analog sensor processing, which takes about 100 µs for the E-727
Duration of the digital filtering. If the
Digital Filter Type
parameter, ID 0x05000000,
is set to "IIR low-pass filter, 2nd order", the required time depends on the cut-off-
frequency f
g
of the IIR low-pass filter which is given by the
Digital Filter Bandwidth
parameter, ID 0x05000001. For signal frequencies f < f
g
/2, the duration of the
filtering can be estimated as follows:
t ≈ 0.216 / f
g
If required, increase f
g
. Examples:
f
g
= 300 Hz:
t = 0.72 ms
f
g
= 1000 Hz:
t = 0.216 ms