Chapter 4 Application Techniques ASDA Series Application Note
4-8 March, 2015
4.2 How to Use E-Cam Function to Compensate Tolerances on
Lead Screw
4.2.1 Description
In the application of precision machinery that adapts an open-loop system, manufacturing
tolerance on pitch of lead crew will cause inconsistency between command and position of
machine. System of ASDA-A2 is able to create a compensative E-Cam curve based on the
measurement of the lead screw to solve this problem, keeping the resolution of command from
the host controller remains the same.
4.2.2 How does the System Work?
4.2.2.1 Inconsistency between Command and Machine Position Caused by
Tolerances on Lead Screw
When pitches on lead screw are identical, the correspondence between command and pitch will
be consistent so no compensation is needed.
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2
3
4
5
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Figure 4.2.1 Command from the Host Controller and the Lead Screw without Tolerance
When pitches are not identical, the distance specified by the command and the actual moving
distance of the lead screw will not be identical. That is, the actual moving distance that every
pulse corresponds to is different. In this case, the resolution of command is changed.
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2
3
4
5
Pitch
tolerance
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Command = 10000 Pulse
Figure 4.2.2 Command from the Host Controller and Lead Screw with Tolerance
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