Campbell CR1000 User Manual

Section 7. Installation
noise, and so increase measurement error. Noise from grid or mains power also
may be transmitted through the transformer, or induced electro-magnetically from
nearby motors, heaters, or power lines.
High-quality power regulators typically reduce noise due to power regulation.
Using the optional 50 Hz or 60 Hz rejection arguments for CRBasic analog input
measurement instructions (see Sensor Support
(p. 303) ) often improves rejection of
noise sourced from power mains. The CRBasic standard deviation instruction,
SDEV(), can be used to evaluate measurement noise.
The main power for the CR1000 is provided by an external-power supply.
7.4.3.1 Vehicle Power Connections
If a CR1000 is powered by a motor-vehicle power supply, a second power supply
may be needed. When starting the motor of the vehicle, battery voltage often
drops below the voltage required for datalogger operation. This may cause the
CR1000 to stop measurements until the voltage again equals or exceeds the lower
limit. A second supply can be provided to prevent measurement lapses during
vehicle starting. The figure Connecting CR1000 to Vehicle Power Supply
(p. 102)
illustrates how a second power supply is connected to the CR1000. The diode OR
connection causes the supply with the largest voltage to power the CR1000 and
prevents the second backup supply from attempting to power the vehicle.
Figure 32. Connecting to Vehicle Power Supply
7.4.4 Uninterruptable Power Supply (UPS)
If external alkaline power is used, the alkaline battery pack is connected directly
to the POWER IN 12V and G terminals (9.6 to 16 Vdc).
A UPS (un-interruptible power supply) is often the best power source for long-
term installations. An external UPS consists of a primary-power source, a
charging regulator external to the CR1000, and an external battery. The primary
power source, which is often a transformer, power converter, or solar panel,
connects to the charging regulator, as does a nominal 12 Vdc sealed rechargeable
battery. A third connection connects the charging regulator to the 12V and G
terminals of the POWER IN connector..
102

Campbell CR1000 Specifications

General

Power Requirements	9.6 to 16 VDC
Data Logger Operating System	CRBasic
Memory	4 MB
Analog Inputs	16 single-ended or 8 differential
Analog Input Resolution	13 bits
Analog Input Range	+/-2.5V
Digital I/O	8
Pulse Counters	2
Communication Ports	RS-232
Operating Temperature	-25°C to +50°C
Pulse Channels	4