Siemens SINUMERIK 840Di Function Manual page 24

Detailed Description
2.1 NC/PLC interface signals
Canceling follow-up mode
Once follow-up mode has been canceled, the machine axis does not have to be homed
again if the maximum permissible encoder limit frequency of the active measuring system
was not exceeded during follow-up mode. If the encoder limit frequency is exceeded, the
controller will detect this:
• DB31, ... DBX60.4 / 60.5 = 0 (homed/synchronized 1 / 2)
• Alarm: "21610 Encoder frequency exceeded"
Monitoring
If a machine axis is in follow-up mode, the following monitoring mechanisms will not act:
• Zero-speed monitoring
• Clamping monitoring
• Positioning monitoring
Effects on other interface signals:
• DB31, ... DBX60.7 = 0 (position reached with exact stop fine)
• DB31, ... DBX60.6 = 0 (position reached with exact stop coarse)
DB31, ... DBX1.5 / 1.6 (position measuring system 1 / 2)
2 measuring systems can be connected to one machine axis, e.g.,
• Indirect motor measuring system
• Direct measuring system on load
Only one measuring system can be active at any one time. All closed-loop control,
positioning operations, etc. involving the machine axis always relate to the active measuring
system.
2-12
Note
If "follow-up mode" is deactivated for a machine axis, which is part of an active
transformation (e.g., TRANSMIT), this can generate movements due to the repositioning
(REPOS) of other machine axes involved in the transformation.
Various NC/PLC Interface Signals and Functions (A2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0