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 100 / 240
Phone +49 721 4846-0, Fax +49 721 4846-1019, Email
Additional Steps and Settings
You can calculate the memory space remaining if you ask with WAV? for the current wave table
length. To release memory space, delete the content of selected wave tables with the WCL
command.
After you send the waveform definition to the wave table (with WAV), it is always a good idea to
check it by reading back the waveform sequence from the controller before actually outputting it.
This can be done by the GWD? command. Note that the response to GWD? does not contain any
offset set with WOS to the wave generator output.
You can add an offset to the output of a wave generator using the WOS command. Thereafter, the
output of the specified wave generator is the sum of the offset value and the wave value:
Generator Output = Current Wave Value
If the wave generator is started with the option "start at the endpoint of the last cycle", the E-727
at the end of each output cycle equates the WOS offset value with the current generator output.
WOS sets the value of the
Wave Offset
parameter, ID 0x1300010b, in volatile memory. You can
also change this parameter with SPA or SEP and save the value to nonvolatile memory with WPA
(switch to command level 1 before with the CCL command).
Deleting wave table content with WCL has no effect on the WOS settings.
For triggering purposes, the wave generator output can be coupled with the digital output lines
OUT1 to OUT3 of the controller (see "Digital I/O Socket" (p. 227)). You should first set the signal
state of the output lines to "low" for all waveform points ("low" is also the power-on default). This
can be done with TWS or TWC. Then use the TWS command to define the trigger actions (high/low
level, rising/falling edge) for selected output lines at selected waveform points. To activate the
Generator Trigger mode for the selected output lines, use the CTO command. Examples see p. 109.
The #9 single-character command can be used to query the current activation state of the wave
generators. The reply shows if a wave generator is running or not, but does not contain any
information about the wave generator start mode (e.g. with DDL). With WGO? you can ask for the
last-commanded wave generator start options (WGO settings).
You can limit the duration of the wave generator output by setting the number of output cycles
with WGC. The waveform itself remains unchanged.
Using the WTR command, you can lengthen the individual output cycles of the waveform. The
duration of one output cycle for the waveform can be calculated as follows:
Output Duration = Servo Update Time * WTR value * Number of Points
where
Servo Update Time is given in seconds by parameter 0x0E000200
WTR value gives the number of servo cycles the output of a waveform point lasts, default is 1
Number of Points is the length of the waveform (i.e. the length of the wave table)
WTR sets the value of the
Wave Generator Table Rate
parameter, ID 0x13000109, in volatile
memory. You can change this parameter also with SPA or SEP and save the value to nonvolatile
memory with WPA (switch to command level 1 before with the CCL command). The value is always
valid for the whole system and cannot be set separately for individual wave generators. The value
of the parameter in volatile memory can be read with the WTR? command.
WTR also sets the type of interpolation to use for the wave generator output. If
Wave Generator
Table Rate
is greater than 1, interpolation helps to avoid sudden position jumps of an axis
controlled by the wave generator.