P3: Basic PLC Program for SINUMERIK 840D sl
13.13 Block descriptions
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
989
13.13.9 FB 11: Brake test
Function
The braking operation check should be used for all axes, which must be prevented from moving in an
uncontrolled manner by a holding brake. This check function is primarily intended for the socalled "vertical axes".
The machine manufacturer can use his PLC user program to close the brake at a suitable moment in time (guide
value every 8 hours, similar to the SI test stop) and allow the drive to produce an additional torque / additional
force equivalent to the weight of the axis. In errorfree operation, the brake can produce the necessary braking
torque/braking force and keep the axis at a virtual standstill. When an error occurs, the actual position value exits
the parameterizable monitoring window. In this instance, the position controller prevents the axis from sagging
and negatively acknowledges the mechanical brake test.
The necessary parameterization of NC and Drive is described in:
References:
Functions Manual Safety Integrated
The brake test must always be started when the axis is at a standstill. For the entire duration of the brake test, the
enable signals of the parameterized axis must be set to enable (e.g. the controller inhibit, feed enable signals).
Furthermore, the signal at the axis/spindle DB31,....DBX28.7 (PLC-controlled axis) is to be set to status 1 by the
user program for the complete duration of the test.
Before activating the signal DB31,....DBX28.7 (PLC-controlled axis) the axis is to be switched as "neutral axis",
e.g. DB31,....DBX8.0-8.3 (assign NC axis to channel) is to be set to channel 0 as well as DB31,....DBX8.4
(activation signal when using this byte) is to be set.
The return message:
• about the current status can be queried in DB31, ... DBB68.
• the Nc via the signal DB31, ... .DBX63.1 (PLC controls axis) is to be awaited before the block is started. The
direction in which the drive must produce its torque/force is specified by the PLC in the form of a "traversing
motion" (e.g., via FC 18).
The axis must be able to reach the destination of this movement without risk of collision if the brake is unable to
produce the necessary torque/force.
Note
Instructions for FC 18
If FC18 is called for the same axis in the remainder of the user program, the calls must be
mutually interlocked. For example, this can be achieved via a common call of this function
with an interlocked common data interface for the FC 18 parameters. A second option is to
call the FC18 repeatedly, in which case the inactive FC18 will not be processed by the
program. A multiple-use interlock must be provided.
To Next Page
Loading...
Need help?
General
