Siemens 611-D, 840C 12.18.11.5 HW/SW limit switches of following drive

08.96 12 Functional Descriptions

12.18.11 GI monitors

12.18.11.5 HW/SW limit switches of following drive

If the following axis traverses beyond an HW or SW limit switch, then an internal limit switch is

simulated for all leading axes depending on the sign of Kü. The effect is the same as if every

leading axis had traversed into contact with an SW limit switch. Accordingly, the channels of

the leading axes (and thus also of the other axes interpolating with the leading axes) are also

stopped. The leading axes can be traversed away from the limit switch (ensure correct

direction of traversal).

If the following axis traverses onto the prelimit switch, then the velocity of the leading axes

which are moving the following axis towards the limit switch is reduced depending on the sign

of Kü (simulated prelimit switch for leading axes).

Leading spindles are stopped (regardless of their rotational direction) as soon as the following

axis reaches a HW/SW limit switch. The spindle cannot be traversed in any direction as long

as the following axis is situated behind a limit switch.

If the leading spindle is being traversed by oscillation or alignment, then the oscillation/

alignment function must be aborted (cancellation of interface signals) once the following axis

has been traversed away from the limit switch before the spindle can be restarted.

The following axis always traverses beyond the limit switches by a few increments because the

following axis stop command cannot be released until the limit switch is reached.

Note:

If a following axis is driven with a leading axis that is moved in follow-up mode using the actual

value link, the following axis cannot be stopped if it overshoots the SW limit switch.

Remedy:

• Stop the leading axis (e.g. external conveyor belt)

• Deactivate the link via the hardware limit switch

SINUMERIK 840C (IA)