Manual
Double Sheet Control System R1000 series L20
with integrated fieldbus interface
Operation
B0063191 / 1.3
98
ROLAND ELECTRONIC GmbH · Otto-Maurer-Str. 17 · DE 75210 Keltern · Phone +49 (0)7236-9392-0 · Fax +49 (0)7236-9392-33
8.3
Averaging time t
a
and Measuring time t
m
Averaging time t
a
Every measuring program allows to choose a time for averaging. This time is the averaging time t
a
.
Possible options for averaging are 8ms, 15ms, 25ms, 50ms 100ms, 250ms.
See also chapter 7.7 „Start-up“, „Program parameter 7“.
Note
Basically: A longer time leads because of averaging to more
accurate measuring values.
The selection of the averaging time has influence on the maximal
velocity of the sheets.
Measuring time t
m
The measuring time t
m
is the time required by the system from "measurement start" to the
outputting of the output signal.
Fig. 85.: Clarification of the measuring time
The measurement time t
m
is derived from the sum when operating via I/O inputs: the set time ta for
averaging and an additional delay time of 5 ms for reading the measurement. When operating via
fieldbus the additional delay is 4 ms.
8.3.1 Maximal allowed transport velocity at Double Sheet Control
The maximum allowed transport velocity of the sheet depends on the sheet length and the selected
time t
a
for averaging. In addition, 4 ms are needed for internal processing.
At an upper threshold "up" = 120% (see program parameters) following empiric formula applies:
Max. allowed transport velocity [m/s] <
Length of sheet [mm]
ta [ms] + 4ms
8.3.2 Measuring at standstill
Please notice when performing measurements at standstill:
•
The minimum retention period is as long as the measurement time (the selected averaging
time).
•
Punctual sheet elevations and contamination, such as dust, leads to wrong measurement
results.
t
m
Messung Start
Measurement Start
Ausgangssignal
Output signal
