6 Applications
6.4.8 Wiring
To ensure the optimum precision of the synchronisation process, the signal of the light
barrier must be supplied to the start/sample input without delay or jitter.
During the synchronisation process, any delay or jitter will lead to a position deviation
based on the following relationship:
If the light barrier has a jitter of ±5 ms, for example, a position deviation of ±90° will result
in the case of n = 3000 rpm. This deviation can only be reduced by way of a better light
barrier.
6.4.9 Compensation of constant delays
Constant delays of a light barrier can be compensated rather well. They will only have an
effect if the conveyor belt runs at variable speed, e.g. when the system is started.
6.4.10 Mechanical compensation (lead)
If the system runs at a speed of 2000 rpm ± 500 rpm, for example, the light barrier can be
positioned in such a manner that the delay is exactly compensated at 2000 rpm. At other
speeds, only the speed difference will be taken into consideration. If, for example, the
system, which is compensated at a speed of 2000 rpm, runs at 2200 rpm, the following
error results if the light barrier has a delay of 10 ms:
6.4.11 Compensation by calculation
If the delay of the light barrier is precisely known, it can be entered into the servo drive as a
lead parameter, e.g. as an offset with regard to a relative target position. When the
synchronisation process starts, the servo drive calculates the required lead based on the
current synchronous position and takes it into consideration in terms of its position
setpoint.
Product manual BL 4000-C Page 114 of 298
To Next Page
Loading...
Need help?
General
