Limit Position Monitoring; Hardware Limit Switch - Lenze 8400 Software Manual

4 Detailed functions of the technology application
4.4 Monitoring functions
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4.4.2

Limit position monitoring

For safety reasons, drives with a limited traversing range must always be made safe using
corresponding safety mechanisms. These are firstly the hardware limit switches, which must effect
a standstill of the axes as quickly as possible during the approaching process. In addition, the
parameterisable software limit positions are to inhibit all travel commands which would entail an
exit of the permissible travel range.
Take the following items into consideration for placing the limit positions:
• The hardware limit switches must be mounted with a sufficient clearance in front of the
mechanical limit positions of the linear axis. The clearance to the mechanical limit position
should be calculated for a quick stop (QSP) from maximum speed, so that in the event of an
error, standstill is attained safely before the mechanical limit position is reached.
• The software limit positions must be placed with a sufficient distance from the hardware limit
switch positions. The distance should be calculated for a quick stop (QSP) from maximum speed
without the hardware limit switches being approached.
4.4.2.1

Hardware limit switch

In the default setting, the two digital inputs DI1 and DI2 are provided for the connection of the
hardware limit switches.
• The connection is configured in a fail-safe fashion (LOW = limit switch activated).
• The two digital inputs are linked with the bLimitSwitchPos and bLimitSwitchNeg monitoring
inputs of the LS_MotionControlKernel system block.

Stop!
The limit switches are only evaluated if the limit switches for the respective operating
mode have been activated (see the following table)!
Operating mode
Homing
Manual jog
Positioning
Parameter
(Block)
C00595/1...2
(LS_MotionControl
Kernel)
Lenze · 8400 "Position Sequencer" technology application · Software manual · DMS 1.0 EN · 07/2014 · TD05
Hardware limit switch effective
Depending on the homing mode selected
(see description of the homing modes in the reference manual/online help of the inverter)
Yes (adjustable in C01230 - bit 2)
Yes
Possible settings
0 No Reaction
1 Fault
3 TroubleQuickStop
4 WarningLocked
5 Warning
6 Information
Info
Response at the activation of limit position
monitoring
• Subcode 1: response at the approach of the
positive limit switch.
• Subcode 2: response at the approach of the
negative limit switch.
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