Introduction 2
Port
Port Name
Function
ALARM_GND Ground connection.
1.2 Connecting Alarm Input/output
Alarm input/output is available on select models.
Connect alarm input device to the alarm input end of the I/O port, see Figure 1-2.
Step 1
Device collects different states of alarm input port when the input signal is idling and
being grounded.
Device collects logic "1" when input signal is connecting to +3V to
+5V or idling.
Device collects logic "0" when input signal being grounded.
Alarm input
Figure 1-2
Connect alarm output device to the alarm output end of the I/O port. The alarm output
Step 2
is open-drain output, which works in the following modes.
Mode A: Level application. Alarm outputs high and low level, and the alarm outlet
is OD, which requires external pull-up resistance (10K Ohm typical) to work. The
maximum external pull-up level is 12V, maximum port current is 300mA and the
default output signal is high level (external pull-up voltage). The default output
signal switches to low level when there is alarm output (As long as the operating
current below 300mA, the output low level voltage is lower than 0.8V).
Mode B: Switch application. Alarm output is used to drive external circuit, the
maximum voltage is 12V and the maximum current is 300mA. If the voltage is
higher than 12V, please use an additional electric relay.
