Reference travel

Controller based homing

Reference travel is implemented in the MOVI-C^® CONTROLLER.

Drive based homing

When reference travel is performed via MC_Home, the inverter function "Reference travel" is executed. Currently, this operating mode is only supported by MOVI-C^® axes.

Deactivated

Reference travel is deactivated. Referencing is not possible.

Zero pulse – negative direction

Referencing is performed to the zero pulse (reference pulse of the encoder). The first search direction is negative. Reference point is the first zero pulse. A reference cam is not required.

Reference cam – negative end

Referencing is performed to the negative end of the reference cam. The first search direction is negative.

Reference cam – positive end

Referencing is performed to the positive end of the reference cam. The first search direction is positive.

Limit switch positive/negative

The reference point is at the end of the left/right limit switch.

Referencing without travel

With this reference travel type, the reference point is set at the current position of the drive. The drive does not perform any movement.

Reference cam flush – positive end

Referencing is performed to a reference cam. The reference cam must start just before or in line with the positive hardware limit switch and must project into the limit switch. Reference travel starts at search speed in positive direction. When the negative end of the reference cam is reached, the drive turns and leaves the reference cam again at retraction speed. If no reference cam is found in the positive direction of rotation, an error is triggered at the positive limit switch. If the positive limit switch is hit during deceleration on the reference cam, this is ignored and referencing is continued.

Reference cam flush – negative end

Referencing is performed to a reference cam. The reference cam must start just before or in line with the negative hardware limit switch and must project into the limit switch. Reference travel starts at search speed in negative direction. When the positive end of the reference cam is reached, the drive turns and leaves the reference cam again at retraction speed. If no reference cam is found in the negative direction of rotation, an error is triggered at the negative limit switch. If the negative limit switch is hit during deceleration on the reference cam, this is ignored and referencing is continued.

Fixed stop positive/negative

Referencing is performed to a fixed stop. The system must be designed so that the fixed stop can withstand the load from the respective speed without damage. The search direction is positive/negative. Reference point is the positive/negative fixed stop.

Information: Any hardware limit switches connected to the inverter are ignored in this reference travel configuration. Risk of jamming and crushing.

Absolute position of encoder

With this reference travel type, only the reference bit is set and the current position of the encoder is adopted as the actual position. The reference travel type is only useful for encoders that have a direct reference to the system, such as linear encoders. The reference offset parameter is not used.

Use drive settings

Only used for drive-based reference travel. Use this setting when a reference type of a particular device is not listed in this list. With this setting, the software module does not parameterize the reference travel of the drives. The reference travel of the drives can be configured manually using the device-specific engineering tool.

Reference to zero pulse

The input specifies whether the zero pulse (reference pulse of the encoder) is used as the reference point. The parameter is used for the following reference travel types:

• Reference cam – negative end
• Reference cam – positive end
• Positive limit switch
• Negative limit switch
• Reference cam flush – limit switch positive
• Reference cam flush – limit switch negative

Reference offset

Reference offset in user units

Search velocity

Speed in user unit(s) used to search for a reference cam or hardware limit switch

Retraction velocity

Speed in user unit(s) used during reference travel in the following cases:

When leaving a reference cam or hardware limit switch. With the reduced speed, the drive can travel exactly to the end of the reference cam or limit switch.

When searching a zero pulse (reference pulse of the encoder).

During reference travel to a fixed stop.

Acceleration

Acceleration at start or direction of rotation of reference travel

Deceleration

Deceleration for stopping or reversing the direction of rotation during reference travel

Got to home position

The parameter specifies whether a home position should be approached after reference travel.

FALSE: The drive stops at the reference point.

TRUE: The drive moves from the reference point to the home position with home velocity.

Home position

Basic position

Home velocity

Homing speed

Jerk time

Jerk time

In position – Window width

Position window for starting homing.

In position hysteresis

Position hysteresis for homing.

Velocity changeover before fixed stop

The input specifies when the search speed changes to retraction speed.

Not selected

Limit switch

Reference cam

Dwell time at fixed stop

Time in ms for how long the fixed stop remains hit as soon as the value defined in the "torque limit fixed stop" parameter is reached. Only after this time the drive is referenced.

Torque limit at fixed stop

Torque limit in % nominal motor torque for referencing to fixed stop. After reaching this limit, the fixed stop remains hit as long as defined in the "dwell time at fixed stop" parameter.