Software Limit Switch - Siemens SINUMERIK 828D Function Manual

A3: Axis Monitoring, Protection Zones
2.2 Axis monitoring
Effectivity
The hardware limit-switch monitoring is active after the control has ramped up in all modes.
Effect
Upon reaching the hardware limit switch, the following occurs:
• Alarm 21614 "Channel <Channel number> Axis <Axis identifier> Hardware limit switch <Direction>"
• The machine axis is braked according to the configured braking behavior.
• If the axis/spindle is involved in interpolation with other axes/spindles, these are also braked according to their
configured braking behavior.
• The traversing keys of the affected machine axis are blocked based on the direction.
2.2.6.2

Software limit switch

Function
Software limit switches serve to limit the traversing range of a machine axis. Per machine axis and per traversing
direction, two (1st and 2nd) software limit switches are available:
MD36100 POS_LIMIT_MINUS (1st software limit switch minus)
MD36110 POS_LIMIT_PLUS (1st software limit switch plus)
MD36120 POS_LIMIT_MINUS2 (2nd software limit switch minus)
MD36130 POS_LIMIT_PLUS2 (2nd software limit switch plus)
By default, the 1st software limit switch is active. The 2nd software limit switch can be activated for a specific
direction with the PLC user program:
DB31, ... DBX12.2 / 12.3 (2nd software limit switch minus / plus)
Effectivity
The software limit switches are active:
• immediately after the successful referencing of machine axis.
• in all operating modes.
Constraints
• The software limit switches refer to the machine coordinate system.
• The software limit switches must be inside the range of the hardware limit switches.
• The machine axis can be moved to the position of the active software limit switch.
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions