Data Acquisition Setup
The Data Acquisition Setup window (Fig. 61) contains a collection of some more advanced Homer settings, regarding primarily:
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Measurement of the detector voltages.
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Measurement timings.
You will need it very rarely. To open the window, click the Homer|More|DAQ Setup menu item.
Modified values will not be accepted until the button is clicked. Invalid entries will be either truncated or replaced by defaults.
To set all values to defaults, click the button, then click the button. Fig. 61 shows the defaults.
Fig. 61. Data Acquisition Setup window.
SIGNAL Group
The SIGNAL group sets:
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Periodicity of the signal measurement.
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Ranges of Analog-to-Digital Converters (ADC) used for signal measurement.
These settings apply to all Waveform modes.
Period
Period defines the Signal Measurement Period in milliseconds. When set to zero (default), there is no delay between two consecutive Measure-Tune-Send (MTS) sequences; otherwise two consecutive measurements are spaced by at least Period milliseconds.
The power-up Period value is defined by the following line in the internal Hom.cfg configuration file:
OnPeriod_ms=0 ;Measurement cycle periodicity [ms] (0 to 65535)
Note: The value in the Period edit box of the SIGNAL group is the same as the value in the Measurement edit box of the PERIODICITY group in the TX Timing window.
Range
Range defines ADC voltage measurement ranges when signal (microwave power) is applied to Homer detectors. The default is Auto (autoranging). Fixed ranges increase measurement speed but also the chance of ADC overflow or an inadequately high range.
The power-up Range value is defined by the following line in the internal Hom.cfg configuration file:
OnRnge=-1 ;Signal measurement range (-1=auto 1=50mV 2=500mV 3=5V)
OFFSET Group
The OFFSET group sets the periodicity and ADC range for the measurement of DC offsets of Homer detectors. Offsets are the output voltages of the detector channels in the absence of input microwave power. To enable offset measurements, microwave signal is blocked from reaching the detectors by solid-state switches (Fig. 1). The settings apply to all Waveform modes.
Period
Period defines the offsets measurement period in seconds. When set to zero, the offsets are measured anytime the signal voltages are measured; otherwise, two consecutive offset measurements are spaced by at least Period seconds. The default is 30 s.
The power-up offset measurement Period is defined by the following line in the internal Hom.cfg configuration file:
OfsPeriod_s=30 ;Offsets measurement periodicity [s] (0 to 120)
Range
Range defines the offset voltages measurement range. However, there is one exception: When
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offsets are measured each time the signal voltages are measured (OfsPeriod_s=0), and
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Range as Signal checkbox is checked (the default),
then the OFFSET Range setting is ignored and the offset measurement ranges are the same as the SIGNAL measurement ranges.
The power-up offset measurement range is defined by the following two lines in the internal Hom.cfg configuration file:
OfsRnge=2 ;Offset measurement range (-1=auto 1=50mV 2=500mV 3=5V)
OfsEqualOn=TRUE ;Make OfsRnge=OnRnge when OfsPeriod_s=0
FREQUENCY Group
The Period value in the FREQUENCY group defines the frequency measurement repetition period in milliseconds. When set to zero (default), frequency measurement takes place each time the signal voltage is measured; otherwise two consecutive frequency measurements are spaced by at least Period milliseconds.
The power-up frequency measurement Period is defined by the following line in the internal Hom.cfg configuration file:
FPeriod_ms=0 ;Frequency measurement periodicity [ms] (0 to 65535)
TEMPERATURE Group
The TEMPERATURE group sets the periodicity and averaging number of Homer internal temperature measurement.
Period
Period defines temperature measurement period in seconds. When set to zero, temperature measurement takes place each time the signal voltage is measured; otherwise, two consecutive temperature measurements are spaced by at least Period seconds. The default is 30 s.
The power-up temperature measurement period is defined by the following line in the internal Hom.cfg configuration file:
TPeriod_s=30 ; Temperature measurement periodicity [s] (0 to 120)
Avrg
Avrg defines the number of temperature samples taken and averaged to compute the resulting temperature reading. The default is 8.
The power-up temperature averaging number is defined by the following line in the internal Hom.cfg configuration file:
Trpt=8 ;Temperature measurement averaging (1 to 16)