Matrox 4Sight-II Installation And Hardware Reference page 78

78 Chapter 5: Matrox 4Sight-II hardware reference
The Matrox
opto-coupling
module
The auxiliary I/O interface directly connects to LVTTL devices. However, to
connect to non-LVTTL devices, you must do so via the Matrox opto-coupling
module.
The Matrox opto-coupling module electrically isolates Matrox 4Sight-II from
external devices associated with the auxiliary I/O interface. Since there is no direct
electrical connection between Matrox 4Sight-II and such devices, your unit will
be protected from potential damage that can be caused if the external devices
experience any kind of electrical irregularity
The Matrox opto-coupling module has two functions, based on the direction of
the signals that pass through it:
• Incoming signals go through an optically-isolated stage. Their signals become
converted into digital signals, which the auxiliary I/O interface can interpret.
• Outgoing signals also go through an optically-isolated stage. When a logical "1"
is written to an auxiliary output bit, the open collector output becomes
conductive, thereby closing the switch and completing the circuit. When a logical
"0" is written to the bit, the open collector output becomes non-conductive,
thereby opening the switch.
Note that the response-time for the opto-couplers on the module is higher than
that of standard LVTTL devices. Please refer to Technical reference for details.
You should also refer to this appendix, for the electrical specifications and limits
of the Matrox opto-coupling module, when developing your applications. Be sure
to calculate and configure the circuitry of the external devices, so that they do not
surpass these limits.
1. Note the voltage requirements for external devices connected to the Matrox opto-cou-
pling module should not exceed 24V.
1
.