Manual
ibaPADU-16-M
9
Programmable Settings of the I/O-Modules
All modules have the same interface (connectors and for parameterization). The
parameterization functionality is normalized. That means even if the individual settings
are different, all modules will have the same interface for the same function (i.e. low
pass edge frequency is set with ONE parameter containing the edge frequency in Hz).
9.1
Sampling Rate
The sampling rate can be programmed via the FOB interface in steps of 100 nanosec-
onds from 40
s (25 kHz) to 2 ms (500 Hz) in M mode and in steps of 1 ms from 1 ms
(1 kHz) to 10 ms (100 Hz) in F mode. The chosen sample rate is then common for all
channels, analog and digital. Each channel has an individual ADC circuit to ensure very
accurate phase matching between channels.
9.2
Analog Modules
9.2.1
Input Gain
Input gain is set to 0 dB (= gain factor 1). Confirmation of setting by responding of de-
vice to the FOB Card is given.
9.2.2
Programmable Low Pass Filter
A programmable 72 dB 6-pole low pass filter is implemented on each channel. Com-
mands sent from the ibaFOB are used to set this filter frequency. The device will re-
spond with his “real” settings to ensure proper calculation.
Specification
Example
Range
Accuracy
Reference
Actual Value
100 Hz to 250 Hz
1 %
126
126.3
250 Hz to 500 Hz
1 %
270
270.3
500 Hz to 1000 Hz
1 %
990
990.1
1000 Hz to 10,000 Hz
10 %
3750
3773.6
10,000 Hz to 25,000 Hz 10 %
21,500
22,222
Note
The programmable digital filter produces modulation component frequencies with
< 72 dB of the maximum signal strength. Therefore, the analysis software should take
this into account.
You may reduce this influence if the parameters are set according to the following rule:
Fs (sample freq.) = N x f
LP
(edge freq. of the low pass filter) where N is 1, 2, 3 to N
26 Issue
2.1