Campbell Scientific CR3000 Micrologger - Manual (Page 42)

Section 4. Quickstart Tutorial
42
Figure 11: Use of RS-232 and digital I/O when reading RS-232 devices
4.1.4 Digital I/O Ports
The CR3000 has eight digital I/O ports selectable as binary inputs or control
outputs. These are multi-function ports. Edge timing, switch closure, and high-
frequency pulse functions are introduced in Pulse Sensors
(p. 39)
and discussed at
length in Pulse
(p. 318).
Other functions include device-driven interrupts,
asynchronous communications and SDI-12 communications. Figure Control and
Monitoring with Digital I/O (p. 42) illustrates a simple application wherein digital
I/O ports are used to control a device and monitor the state (whether on or off) of
the device.
Figure 12: Control and monitoring with digital I/O