58
•
Xtium2-CL MX4 Reference
Xtium2-CL MX4 User's Manual
Shaft Encoder Interface Timing
Dual Balanced Shaft Encoder RS-422 Inputs:
•
See
J1: Internal I/O Signals Connector (26-pin SHF-113-01-L-D-RA)
and
J2: Internal I/O Signals Connector (40-pin TST-120-01-
for complete connector signal details.
Web inspection systems with variable web speeds typically provide one or two synchronization
signals from a web mounted encoder to coordinate trigger signals. These trigger signals are used
by the acquisition line scan camera. The Xtium2-CL MX4 supports single or dual phase shaft
encoder signals. Dual encoder signals are typically 90 degrees out of phase relative to each other
and provide greater web motion resolution.
Example using any Encoder Input with Pulse-drop Counter
When enabled, the triggered camera acquires one scan line for each shaft encoder pulse-edge. To
optimize the web application, a second Sapera parameter defines the number of triggers to skip
between valid acquisition triggers. The figure below depicts a system where a valid camera trigger
is any pulse edge from either shaft encoder signal. After a trigger, the two following triggers are
ignored (as defined by the Sapera pulse drop parameter).
K
D
D
K
D
D
K
D
D
K
D
D
K
D
D
Shaft Encoder phase A
Shaft Encoder phase B
K = Keep
D = Drop or Skip
Note: in this example, Number of trigger to drop = 2
Line acquired
Figure 18: Encoder Input with Pulse-drop Counter
