USER'S MANUAL, VERSION 2.0
Copyright © Convergence Systems Limited 2021, All Rights Reserved
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GPIO Ports Connection Guide
The CSL Fixed Intelligent Reader Family’s GPIO ports are actually optically isolated switches
only. There are various ways one can connect them up for common peripheral control. The
following sub-chapters describe typical ways to connect up for General Purpose Input and
General Purpose Output operations.
In addition to 4 optically isolated GPO and 4 optically isolated GPI, the CSL fixed intelligent
reader family also supply an isolated 12 Volt DC supply at 2 Watt, i.e., a maximum of 160 mA
current drive output. For low power peripheral devices, including most relays, this 12 Volt
isolated DC power supply can be used to drive them.
For load that requires higher current drive, external power supply is needed, and some of the
examples show how this is done in a safe manner. The important thing to remember is to
handle exception cases when the load encounters a shorting failure, so that unlimited current
can pass through that, and the optical isolated switch can be damaged if a protective resistor
(high power resistor) is not placed in series with the power supply path. As long as a
protective resistor is there, the overall circuit is protected. This is a standard industry practice.
