Campbell Scientific CR23X Micrologger - Manual (Page 15)

CR23X MICROLOGGER OVERVIEW
OV-5
Return currents from the CAO and pulse-
counter channels should be tied to the
terminals in the CAO and pulse-counter
terminal strip to prevent them from flowing
through the analog measurement section.
The ground lug is also marked and provides
a rugged ground path from the individual and
G terminals to earth or chassis ground for ESD
protection.
Review Section 14.7 for complete grounding
recommendations.
OV1.1.8 5V OUTPUTS
The 5 V (
±
4.0%) output is commonly used to
power peripherals such as the QD1 Incremental
Encoder Interface, AVW1 or AVW4 Vibrating
Wire Interface.
The 5 V output is common with pin 1 on the CS
I/O 9 pin connector; 200 mA is the maximum
combined output.
OV1.1.9 CS I/O
The 9 pin CS I/O port contains lines for serial
communication between the CR23X and
external devices such as computers, printers,
Campbell modems, Storage Modules, etc. This
port does NOT have the same configuration
as the 9 pin serial ports currently used on
most personal computers. It has a 5 VDC
power line which is used to power peripherals
such as Storage Modules. The same 5 VDC
supply is used for the 5 V output on the lower
right terminal strip. It has a 12 VDC power line
used to power other peripherals such as the
COM200 phone modem. Section 6 contains
technical details on serial communication.
OV1.1.10 COMPUTER RS-232 PORT
This port is an optically isolated standard 9 pin
RS-232 DCE/DTE port. It can be connected
directly to the serial port of most personal
computers. A 6 foot 9 to 9 pin serial cable and a
9 to 25 pin adapter are included with the CR23X
to connect this port to a PC serial port.
OV1.1.11 SWITCHED 12 VOLT
The switched 12 volt output can be used to
power sensors or devices requiring an
unregulated 12 volts. The output is limited to
600 mA at 50°C (360 mA at 80°C) current. The
switched 12 volt port is addressed as “Port 9” in
a datalogger program.
When the port is set high, the 12 volts is turned
on; when the port is low, the switched 12 volts is
off (Section 8.12).
OV1.2 CONNECTING POWER TO THE CR23X
The CR23X should be powered by any clean,
battery backed 12 VDC source. The green
power connector on the wiring panel is a plug in
connector that allows the power supply to be
easily disconnected. The power connection is
reverse polarity protected. The datalogger
should be earth or chassis ground during
routine operation. See Section 14 for details on
power supply connections and grounding.
When primary power falls below 11.0 VDC, the
CR23X stops executing its programs. The Low
Voltage Counter (
∗B window 9) is incremented
by one each time the primary power falls below
11.0 VDC and E10 is displayed. A double dash
(--) in the 9th window of the
∗B mode indicates
that the CR23X is currently in a low primary
power mode. (Section 1.6)
The datalogger program and stored data
remain in memory, and the clock continues to
keep time when power is disconnected. The
clock and SRAM are powered by an internal
lithium battery. (Section 14.11.2)
OV2. MEMORY AND PROGRAMMING
CONCEPTS
OV2.1 INTERNAL MEMORY
The standard CR23X has 512 Kilobytes of
Flash Electrically Erasable Programmable
Read Only Memory (EEPROM), 128 Kilobytes
Static Random Access Memory (SRAM), and 1
Megabyte of Flash RAM. As an option, the
CR23X can be purchased with 4 Megabyte
Flash for final storage. Operating system
EEPROM stores the operating system, user
programs, and labels. SRAM is used for final
storage data and running the user program.
Final Storage Flash is used for data storage.
The use of the Input, Intermediate, and Final
Storage in the measurement and data
processing sequence is shown in Figure
OV2.1-2. The five areas of SRAM are: