Cam configuration

A cam switches a digital output within a certain angle range during a cam encoder revolution. Several cams can be defined for one output, so that the output signal can be switched several times during a revolution.

Three different cams are available. A distance cam (also referred to as position cam) switches on an output at a certain position and switches it off again at a different position. A time cam switches on an output at a certain position and keeps it active for a certain period. A brake cam has a special function during the braking process.

Right-click on Cam Group 1 to insert a new cam.

A dialog box opens, in which the name and type of the cam can be specified.

Distance Cam
Time Cam
Brake Cam

Distance cams

After a distance cam was inserted the parameters can be configured.

Start Position: Angle position during an encoder revolution at which a digital output is switched on.
Ending Position: Angle position during an encoder revolution at which the digital output is switched off again.
Cam Line: Number of the digital output that is switched by this cam. The outputs are numbered starting from 0.
Counter Value: This value defines whether the cam is activated during each revolution or only during each n-th revolution. A value of 0 switches the cam off altogether. For a proper function a minimum value of 1 must therefore be specified.
Standard Active: The cam is entered in the standard cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (standard if ReverseMode=0).
Reverse Active: The cam is entered in the reverse cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (reverse if ReverseMode=1).
Dynamic Enabled: The cam controller calculates a velocity-dependent position correction if this parameter is TRUE. At higher velocities the cam therefore switches earlier. The correction can be configured via Preset Time.
Preset Time: Rate time for compensating switching times of an actuator connected to an output (integer value in 100 µs steps). The rate time only takes effect when the dynamic function is switched on (Dynamic Enabled).
Hysteresis Enabled: not implemented
Increments for Hysteresis: not implemented

Time cams

Time cams cannot be configured together with distance or brake cams on the same output. Depending on the switching time and the velocity, only one time cam should be configured per output track.

Start Position: Angle position during an encoder revolution at which a digital output is switched on.
Duration: Switch-on time of the cam as integer value in 100 µs steps.
Cam Line: Number of the digital output that is switched by this cam. The outputs are numbered starting from 0.
Counter Value: This value defines whether the cam is activated during each revolution or only during each n-th revolution. A value of 0 switches the cam off altogether. For a proper function a minimum value of 1 must therefore be specified.
Standard Active: The cam is entered in the standard cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (standard if ReverseMode=0).
Reverse Active: The cam is entered in the reverse cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (reverse if ReverseMode=1).
Dynamic Enabled: The cam controller calculates a velocity-dependent position correction if this parameter is TRUE. At higher velocities the cam therefore switches earlier. The correction can be configured via Preset Time.
Preset Time: Rate time for compensating switching times of an actuator connected to an output (integer value in 100 µs steps). The rate time only takes effect when the dynamic function is switched on (Dynamic Enabled).
Hysteresis Enabled: not implemented
Increments for Hysteresis: not implemented

Brake cams

A brake cam has a special function. The allocated output (Cam Line) is initially active during normal operation, as long as the PLC has set the Break Enabled variable allocated to the output track in the process image. To initiate a braking process, the PLC sets Break Enabled to 0. As a result, the output track is switched off at the parameterised angle position.

Brake cams cannot be configured together with distance or time cams on the same output. Only one brake cam can be configured for each output track.

Brake Position: Angle position during an encoder revolution, at which a digital output is switched off when the brake is deactivated in the PLC (Break Enabled in the process image)
Cam Line: Number of the digital output that is switched by this cam. The outputs are numbered starting from 0.
Counter Value: This value defines whether the cam is activated during each revolution or only during each n-th revolution. A value of 0 switches the cam off altogether. For a proper function a minimum value of 1 must therefore be specified.
Standard Active: The cam is entered in the standard cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (standard if ReverseMode=0).
Reverse Active: The cam is entered in the reverse cam table if this parameter is TRUE.
The cam controller manages two cam tables. Via the variable ReverseMode in the process image the PLC defines whether the standard cam table or the reverse cam table is active (reverse if ReverseMode=1).
Dynamic Enabled: The cam controller calculates a velocity-dependent position correction if this parameter is TRUE. At higher velocities the cam therefore switches earlier. The correction can be configured via Preset Time.
Preset Time: Rate time for compensating switching times of an actuator connected to an output (integer value in 100 µs steps). The rate time only takes effect when the dynamic function is switched on (Dynamic Enabled).
Hysteresis Enabled: not implemented
Increments for Hysteresis: not implemented

Position resolution

Cam start and end positions can be specified with a resolution of 1/1000 degree. However, please note that the cam controller internally operates with two possible resolutions and rounds the defined position to the internal resolution. Depending on the encoder configuration (see parameter Use Encoder Precision) the cam controller operates with 360 steps or with the full encoder resolution (encoder increments per revolution)