Dynalco SWT-1000 Speed Switch/Transmitter - Manual (Page 19)

Operating Instructions SWT-1000 DYNALCO
SWT-1000.r2.0609 17
8. Operating Behavior
8.1 Power On
8.1.1 Analog Output
Following power on the output assumes the output range start value. Upon completion of the first
measurement the output goes to the corresponding measured value.
Relay Output
The parameter set determined by the configuration and binary input is valid from the start.
If the relay is assigned to a limit it remains deactivated until completion of the first measurement,
following which it assumes the status defined under Limit.
If the relay is assigned to any other item in the status register it immediately assumes the
corresponding status.
If no input frequency is present then after a period of 2 x Fixtime a measured value below the
lower set point is assumed.
8.2 Measurement
Every measurement begins with the positive edge of the input signal. Once the Fixtime has lapsed
the next positive edge ends the running measurement and starts the next.
The resulting effective measurement time is dependent upon whether the input signal period is
longer or shorter than the Fixtime.
Input signal period < Fixtime Input signal period > Fixtime
Input
Frequency
End of Fixtime Ensuing edge
Fixtime
Input period time
Effective measurement period
t
Measurement typically
= Fixtime
t
Measurement max
= 2 x Fixtime
Input
Frequency
End of Fixtime Ensuing edge
Period of input signal
Fixtime time Fixtime
Effective measurement period
t
Measurement max
= 2 x Input signal period
The total measurement time has a resolution of
± 0.4 μs. The calculation and adaptation of
outputs follows immediately after the Fixtime. With input frequencies outside of the measuring
range, the corresponding final values are assumed.
8.2.1 The Adaptive Trigger Level
After triggering, the trigger level is set for the
next pulse anew.
This guarantees that the trigger level can follow
a 50% reduction in speed from pulse to pulse.
DC offset, resonance and negative pulses have
no influence on the triggering
t
trigger level
signal to
noise ration
bad sensor
signal
U
old trigger level