12 Functional Descriptions 07.97
12.13 Indexing function from the PLC
12.13 Indexing function from the PLC
Corresponding data
• MD244*
1104*
1108*
1112*
MD 564* bit 3
MD 564* bit 4
MD 5018 bit 4, division from PLC (this bit must be set to 1, otherwise the indexing axis is
not activated)
• General
• Division in set-up mode
• Division from the PLC
• Explanation of indexing function terms
• Machine data
• Traversing an indexing axis to the reference point
• Monitoring
• Alarms
• Actual value display
• PLC user interface
• Conditions
• Error messages from the NC to the PLC
General
NC axes in (rotary and linear axes) can be positioned at certain grid points using the indexing
function from the PLC (setup mode division related).
This function is used for various applications such as positioning auxiliary axes (turrets, tool
magazines) as well as for machining teeth (gear machining, tool grinding).
The initial setting of this function and the parameters are set in the machine data.
Positioning in the indexing grid is carried out with traversing keys ”+” and ”–” in JOG or INC
mode. It is also possible to traverse an NC axis to the desired indexing position from the PLC
via the command channel in NC modes AUT, MDA, JOG, INC and REPOS.
The divisions are calculated in such a way that no additive indexing errors occur. Absolute
reference to setpoint and actual position means that the same starting position is always used
in calculation. In the case of a rotary axis, the same starting position is always reached even
after several revolutions.
Even where a division leaves a remainder, indexing positions are calculated to a tolerance of
0.5
.
input resolution and approached.
12–102 © Siemens AG 1992 All Rights Reserved 6FC5197- AA502
SINUMERIK 840C (IA)