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FLOWSIC200 · Operating Instructions · 8013271/1CJ9/V2-0/2022-01 · © SICK Engineering GmbH
Product description
2.4
Check cycle
A check cycle can be triggered on the FLOWSIC200 to test whether the device components
are functioning correctly. The check cycle can also be triggered automatically (the interval
can be set using SOPAS ET) and/or via a digital input (
). Any deviations from
normal behavior are output as a warning or error.
If a malfunction is present or a warning is displayed, a check cycle can be triggered
manually to locate the cause of the problem (see Service Manual).
The check cycle comprises a zero point control and span test. The check values can be
output via the analog output. The progress of the check cycle is output on the
corresponding relay and, when the display module option is used, indicated by the text
“Check cycle” on the display.
2.4.1
Zero point check
A special circuit arrangement in the sender/receiver units ensures transmission signals
from the transducers can be read back without delay and with the original waveform. These
transmission signals are received as reception signals, amplified, demodulated, and
evaluated. If the device is operating correctly, the exact zero point is calculated here. This
check comprises a full check of all the system components, including the transducers. A
warning is output for offsets greater than approx. 0.25 m/s (depending on the measuring
path and gas temperature). In this case, check the transducers and electronic components.
If the signal amplitude or waveform does not match the expected values, the transducers or
electronic components are defective and, in this case, an error message is output.
2.4.2
Span test
During the electronic zero point test, the time difference between both directions of signal
transmission is determined and computed with the system parameters gas temperature,
measuring distance and sound velocity as a velocity offset at the zero point. This offset is
added to the selected span value and output. The span value can be set to between 50 and
70% in 1% steps using SOPAS ET (default value from the factory 70%). The complete
measuring system will respond in the prescribed manner when all system components are
intact.
If the check cycle is not output on the analog output, the last measured
value is output for the duration of the check cycle (approx. 20 s when the
check runs correctly).
To trigger a zero point control and span test, as well as a check cycle via a
digital input, a contact must be closed at the corresponding terminals for at
least 2 s.
Automatic check cycles are carried out periodically from the configured time
interval, until the interval setting is changed (or the device is reset). After a
device reset (or power failure), the check cycle begins at the defined time
when the device resumes operation.
If the automatic check cycle and check cycle triggered via a digital input
occur at the same time, only the cycle triggered first takes effect.
