Laser beta lasermike LS8000-3 Manuel D’Utilisation

Page de 221
LaserSpeed 8000-3 Instruction Handbook
 
Installing the System 
 
 
Part No. 93463 / Drawing No. 0921-01561 
Page 33 of 221 
Revision A (Sep 2007) 
Starting/Ending Length Correction 
The Validation Time Limit feature is used because the Material Present signal 
tells the gauge that material is indeed moving through the measurement zone.  
If valid velocity measurements cannot be made, then a small amount of length 
will not be accumulated which, in turn, will cause a length error.  This may or 
may not be a problem, depending on the velocity of the material when it 
passes through the measurement volume during this time.  The start-up 
length-correction is executed to obtain a more accurate length reading.  Each 
measurement update is divided into small subintervals.  When the Material 
Present signal is received within an update period, the time it was received is 
recorded with a subinterval clock.  The length is calculated by using valid 
velocity and integrating over the time measured with the subinterval clock.  For 
example, if the material speed is 10 meters per minute and material enters the 
measurement volume in the middle of the 1-millisecond update period, the 
subinterval time of 0.5ms is used to calculate length rather than the 1-
millisecond period.  In this case, a 0.083 mm correction would be made.  The 
same type of correction is made when the material leaves the measurement 
volume. 
If problems are encountered during any of the installation steps, contact Beta 
LaserMike for assistance.