3M 1000, User Manual

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9
Configuring Digital I/Os
76 3M Compact RFID Reader 1000 User’s Guide
8
Configuring Digital Inputs and Outputs
8.1.
Digital Inputs
The digital inputs (DIN1 – DIN4) can be used as general purpose inputs or
to trigger the reader for tag reading. Unused or open digital inputs are
floating inside the reader.
To activate the input, pull it low (0 Vdc) with an external device or
connection to ground that can sink 2.5 mA. No voltage higher than +24 Vdc
or lower than 0 Vdc should ever be connected to the input. See Figure 5 for
an example of a typical motion sensor installed as a tag read trigger device.
8.2.
Digital Outputs
The digital outputs (DOUT1 – DOUT4) can be used as general purpose
outputs, to indicate tag reading activity, or to indicate the reader is
transmitting (RF On). Digital outputs can be pulled high.
No voltage higher than +40 Vdc or lower than 0 Vdc should ever be
connected to a digital output. The reader activates the output by pulling it
low (0 Vdc) and can sink current such that power dissipation is
≤ 1W.
8.3.
Low Latency Digital Input/Output Operation
The 1000 is equipped with low-latency digital inputs and outputs. The
inputs (3 and 4) can be used by the modem to trigger low-latency events.
Two commands control these inputs as follows:
modem.dio.in.X.positive_level = Y
-- if X goes high, it triggers Y
modem.dio.in.X.negative_level = Y
-- if X goes low, it triggers Y
where
Y
can be:
NOOP
(default)
ACTIVE_MODE
STANDBY_MODE
TOGGLE_MODE
ONE_ROUND
(performs one inventory round, nonblock)
RUN_SCRIPT
(runs series of modem commands, see the following)
Digital I/O Module
An optional Digital
I/O Module is
available for the
3M Compact RFID
Reader 1000.
Refer to Appendix A
for more