Software Limit Switches

Description

Movements can be monitored using software limit switches. A positive position limit and a negative position limit can be set for monitoring.

If the positive or negative position limit switch are reached, the movement stops. An error message is generated and the operating state switches to 7 Quick Stop Active.

The error message can be reset by means of a “Fault Reset”. The operating state switches back to 6 Operation Enabled.

The movement can continue, however, only in the opposite direction of the position limit. For example, if the positive position limit was reached, further movement is only possible in negative direction. In the case of further movement in positive direction, a new error message is generated and the operating state switches back to 7 Quick Stop Active.

Prerequisite

Software limit switch monitoring only works with a valid zero point, see Size of the Movement Range.

Behavior in Operating Modes with Target Positions

In operating modes with target positions, the movement is started even if the target position is beyond the positive position limit or the negative position limit. The movement is stopped so that the motor comes to a standstill at the position limit. After standstill, the drive transitions to the operating state Quick Stop Active.

In the following operating modes, the target position is verified prior to the start of a movement so that the position limit is not exceeded regardless of the target position.

  • Jog (step movement)

Behavior in Operating Modes Without Target Positions

In the following operating modes, a Quick Stop is triggered at the position limit.

  • Jog (continuous movement)

The parameter MON_SWLimMode allows you to set the behavior when a position limit is approached.

Parameter name

HMI menu

HMI name

Description

Unit

Minimum value

Factory setting

Maximum value

Data type

R/W

Persistent

Expert

Parameter address via fieldbus

MON_SWLimMode

Behavior when position limit is reached.

0 / Standstill Behind Position Limit: Quick Stop is triggered at position limit and standstill is reached behind position limit

1 / Standstill At Position Limit: Quick Stop is triggered in front of position limit and standstill is reached at position limit

Type: Unsigned decimal - 2 bytes

Write access via Sercos: CP2, CP3, CP4

Modified settings become active immediately.

-

0

0

1

UINT16

R/W

per.

-

Modbus 1678

IDN P-0-3006.0.71

Standstill at the position limit in operating modes without target position requires the parameter LIM_QStopReact to be set to "Deceleration ramp (Quick Stop)", see Stopping Movement with Quick Stop. If the parameter LIM_QStopReact is set to "Torque ramp (Quick Stop)", the movement may come to a standstill in front of or behind the position limit due to different loads.

Activation

The software limit switches are activated via the parameter MON_SW_Limits.

Parameter name

HMI menu

HMI name

Description

Unit

Minimum value

Factory setting

Maximum value

Data type

R/W

Persistent

Expert

Parameter address via fieldbus

MON_SW_Limits

Activation of software limit switches.

0 / None: Deactivated

1 / SWLIMP: Activation of software limit switches positive direction

2 / SWLIMN: Activation of software limit switches negative direction

3 / SWLIMP+SWLIMN: Activation of software limit switches both directions

Software limit switches can only be activated if the zero point is valid.

Type: Unsigned decimal - 2 bytes

Write access via Sercos: CP2, CP3, CP4

Modified settings become active immediately.

-

0

0

3

UINT16

R/W

per.

-

Modbus 1542

IDN P-0-3006.0.3

Setting Position Limits

The software limit switches are set via the parameters MON_swLimP and MON_swLimN.

Parameter name

HMI menu

HMI name

Description

Unit

Minimum value

Factory setting

Maximum value

Data type

R/W

Persistent

Expert

Parameter address via fieldbus

MON_swLimP

Positive position limit for software limit switch.

If a user-defined value entered is outside of the permissible range, the limit switch limits are automatically set to the maximum user-defined value.

Type: Signed decimal - 4 bytes

Write access via Sercos: CP2, CP3, CP4

Setting can only be modified if power stage is disabled.

Modified settings become active the next time the power stage is enabled.

usr_p

-

2147483647

-

INT32

R/W

per.

-

Modbus 1544

IDN P-0-3006.0.4

MON_swLimN

Negative position limit for software limit switch.

See description 'MON_swLimP'.

Type: Signed decimal - 4 bytes

Write access via Sercos: CP2, CP3, CP4

Setting can only be modified if power stage is disabled.

Modified settings become active the next time the power stage is enabled.

usr_p

-

-2147483648

-

INT32

R/W

per.

-

Modbus 1546

IDN P-0-3006.0.5