CHAPTER 2
R
EADER
H
ARDWARE
I
NSTALLATION AND
O
PERATION
ALR-9890 – RR H
ARDWARE
S
ETUP
G
UIDE
D
OC
. C
ONTROL
#8102
XXX
-000-000 R
EV
A
13
Input Configuration
The Reader includes four optically isolated inputs. These may be used to notify
the reader of external events. The reader can react to and/or report the
occurrence and timing of input events. The reader inputs are designed to accept
a 5 volt signal. The absolute maximum is 8 volts. The user must supply an
external fixed voltage power supply to drive the optically isolated circuits.
The input circuit consists of a 1 kohm resistor in series with a photo diode. The
cathode of the diode is connected to the V- pin of the IO connector. The input is
energized by sup5 volts DC between the input pin and the V- pin of the
IO connector. The input is de-energized by opening the connection to the input
pin of the connector.
The external power supply can be 12 or 24 volts. A quarter watt resistor is
required in the input circuit so that the voltage to the input is approximately 5
volts when energized. The resistor value for 24 volts is ~3.6 kohm athe input
circuit to account for all voltage drops and power dissipation for proper operation
and reliable performance in the intended application.
You are now ready to bench test or demonstrate the RFID Reader system.
