Siemens Milltronics BW500, Operating Instructions Manual

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Recalibration
7.4 Recalibration
BW500 and BW500/L
76
Operating Instructions, 12/2016, A5E33482052-AD
7.4.4 Auto Zero
The Auto Zero function is useful in outdoor applications where there are fluctuations in
temperature, causing the zero to change throughout the day.
Auto Zero provides automatic zero calibration in the RUN mode under the following conditions:
● the auto zero input (terminals 29/30) is in a closed state; jumper or remote contact
● the load on the belt is within the programmed percentage (P371) based on the design load
(P952)
Note
Set Parameter P371 to a value from 1 to 10%, default is 2%. See “P371 Auto Zero
Initiation Upper Limit (Page 171)"
● the terminal and load status coincide for at least one belt revolution
The rate display is interrupted by the Auto Zero routine.
Rate
Total 1:
0.00 t/h
0.00 tonnes AZ
(AZ flashes on and off)
Note
t/h equals metric tonnes per hour
Calibration Complete. Deviation
Auto-Zero value
0.0
551410
For example, typical zero and deviation values.
The duration of the auto zero is one or more belt revolutions (P360). If either condition is
interrupted during that period, the auto zero is aborted and the RUN display is resumed. After
one belt revolution, another auto zero will be attempted if the input and load conditions are met.
If the resulting zero deviation is less than an accumulated 2% from the last operator initiated
zero, the auto zero is accepted.
If the deviation is greater than an accumulated 2%, an error message is displayed. The error
message is cleared after five seconds, however if a relay is programmed for diagnostics, it
remains in alarm so long as the Auto Zero conditions are being met.
If material feed resumes during an auto zero function and is greater than the maximum load on
the belt (P371), the totalizing function is maintained.