Introduction to the electronic cam module
Cam processing operation
Role of the
Tracks and the
Cams
A track is made up of one or more cams. It controls a physical output of the module.
A cam defines an action on the output in a position reading interval.
Example of a cam in active position in both forward and reverse directions: the output associated to the track is activated when the angular reading is between 2 position values, X1 and X2 (when moving in either direction.).
State of the Encoder rotation
Forward
Forward direction
Reverse direction
Analogy with
Mechanical
Cams
The following illustration shows a mechanical equivalent of the electronic cam.
Encoder Track 0 Track 1 Track n
Cams
Position
Output
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Introduction to the electronic cam module
Operation The following table describes the operation of a track to which 2 cams are associated:
Phase Phase Description
1 The axis turns forward and drives the position encoder.
The module calculates the position reading by evaluating the encoder increments.
Track i is not active, output Qxy.i is at 0.
2 When threshold X1 on cam 0 is reached: l l track i becomes active, output Qxy.i switches to 1.
3 When threshold X2 on cam 0 is reached: l l track i becomes inactive, output Qxy.i switches to 0.
4 When threshold X1 on cam 1 is reached, l l track i becomes active, output Qxy.i switches to 1.
5 When threshold X2 on cam 1 is reached, l l track i becomes inactive, output Qxy.i switches to 0.
6 The axis continues to rotate and the process is repeated (returns to phase no. 1).
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3 types of cam
Introduction to the electronic cam module
The following table describes the 3 types of cam available. These cams can be active in forward or reverse direction, or forward and reverse simultaneously.
Type of cam
Position (See Cam in
position, p. 93)
Monostable (See
Monostable cam, p. 96)
Braking (See Breaking
cam, p. 97)
Role
A position cam is a cam whose logic state depends on the position of the axis in relation to 2 thresholds.
A monostable cam is one which switches to 1 when a threshold is crossed and returns to 0 after a time delay. This function is suitable for slow shaft detection.
A brake cam is one which switches to 1 when a threshold is crossed and returns to 0 when the same threshold is crossed in the opposite direction. This function is suitable for controlling braking at the top dead center of the machine.
Associated
Functions
In addition to the basic functions, the electronic cam module provides the following functions:
Function
Feedforward (See
Parametering for the
tracks, p. 89)
Parallel track (See
Parametering for the
tracks, p. 89)
Event (See Parametering
for the tracks, p. 89)
Parts counter (See
Parametering for the
parts counter, p. 87)
Role
Compensates for the delay caused by the machine’s actuators.
Makes 2 tracks in one group parallel.
Triggers an event each time the track is switched.
Manages the number of parts processed or cycles performed and reacts on the process when the counter has reached the limit value.
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