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 28 / 240
Phone +49 721 4846-0, Fax +49 721 4846-1019, Email
The following parameters determine the digital filter settings:
Digital Filter Type
parameter ID 0x05000000
0 = no filter
1 = IIR low-pass filter, 2nd order
99 = USER filter (coefficients of the filter are given by
User Filter Param. 1
to
5
(IDs
0x05000101 to 0x05000105)
Digital Filter Bandwidth
parameter ID 0x05000001
Gives the cut-off-frequency f
g
of the IIR low-pass filter. Only used if "Digital Filter
Type" is set to "IIR low-pass filter, 2nd order".
Note that the duration of the signal processing for a sensor results from two
portions:
1) Duration of the analog sensor processing, which takes about 100 µs
2) Duration of the digital filtering which depends on the f
g
setting: for signal
frequencies
f < f
g
/2, the duration of the filtering can be estimated as follows:
t ≈ 0.216 / f
g
In PIMikroMove, the digital filter parameters are available in the
Sensor Mechanics
parameter
groups in the
Device Parameter Configuration
window.
Polynomial linearization is used to correct system performance. The basic form of the polynomials
is as follows:
To make the system components easily replaceable, sensor (i.e. mechanics) and electronics use
separate polynomials. The coefficients of the polynomials are determined at the factory. Some
terms of the polynomials are provided for future application and presently set to zero. The
following terms are currently in use:
Electronics linearization: offset, gain, 2
nd
, 3
rd
and 4
th
order correction. The
corresponding coefficients of the polynomial are given by the parameters
0x03000100 to 0x03000500. They are independent of the connected mechanics and
may not be changed by the user. In PIMikroMove, these parameters are available in
the
Sensor Electronics
parameter groups in the
Device Parameter Configuration
window.
Mechanics linearization: offset, gain, 2
nd
, 3
rd
and 4
th
order correction. The
corresponding coefficients of the polynomial are given by the parameters
0x02000200 to 0x02000600. They depend on the connected mechanics. In
PIMikroMove, these parameters are available in the
Sensor Mechanics
parameter
groups in the
Device Parameter Configuration
window.
For the internal sensors in the mechanics, the parameters should not be changed by
the user. For analog input lines (E-727.xxxA, .xxxAx only; see p. 22 for details),
changing the offset and gain values is required to scale the analog input to suitable