11
trigger pulls it low. When operating as an output, the GPIO pin is a current limited,
open collector output. When “off”, the output will “leak” about 0.3 mA to ground if
connected to a positive voltage. When “on” it can sink 100 mA to ground, with a
saturation voltage of approximately 2.4 volts. This makes the output ideal for
driving relay coils, but it may or may not drive devices intended to operate from TTL
or dry contact closures. You will need to know the trigger threshold of the device to
be sure that it is compatible with the GPIO ports on the Flex. If you are unsure or if
your device’s trigger voltage is below +2.4VDC or your device requires a “dry”
contact closure, you should interface your device through an IT‐R4S serial relay
module, the K‐10D relay module or one of the other K Series relay modules. The IT‐
R4S will interface to the Flex via one of the serial ports while the relay module will
interface through the GPIO ports. The IT‐R4S has a serial pass‐through port to allow
another device to be connected to it. This allows 2 devices to share 1 serial port on
the Flex. The I/O Ports are to be wired as shown below
:
Analog
Input
The FLEX panel has one analog input. This input will receive a 0 to 10 volt DC range
signal.
NOTE:
The
analog
input
is
designed
for
future
use.
