Cognex MVS-8000 Series, Hardware Manual

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2 MVS-8600 Hardware
MVS-8600 Hardware Manual 77
I/O Connection Module Output Circuitry
Figure 28 shows a typical output schematic to help you determine how to wire strobe
output devices to the opto-isolated S
n + and S n – pins of the J8 and J10 jacks of the I/O
connection module.
Figure 28. Schematic for opto-isolated strobe output on I/O connection module
I/O Connection Module Adds Conversion Delay
The opto-isolated trigger and strobe connection options on the I/O connection module
converts the digital TTL signals from the MVS-8600 into opto-isolated signal pairs. The
opto-isolation circuitry of the I/O module adds a very small delay compared to a pure
TTL signal. For comparison, the response time of a typical TTL signal is about 1
microsecond.
A strobe device will receive its signal about 2.0 microseconds slower when connected
to the opto-isolated jacks of the I/O module than when connected to the TTL jacks.
A signal from a trigger device connected to the opto-isolated jack will be delayed from
reaching the MVS-8600 by about 1.5 microseconds, compared to the same device
going through the TTL jack.
A delay of this small magnitude is not visible to the naked eye, but may have a
cumulative effect when multiplied over many rapid image acquisitions. Take this delay
into account when calculating your maximum image processing throughput if you plan
to use the opto-isolated jacks of the I/O connection module.
Opto-isolator
S n
S n –
1.5K

VCC
330

S n +
From MVS-8600