Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 25)

1-1
Section 1. Installation and Maintenance
1.1 Protection from the Environment
The normal environmental variables of concern are temperature and moisture.
The standard CR5000 is designed to operate reliably from -25 to +50°C (-40°C
to +85°C, optional) in noncondensing humidity. When humidity tolerances are
exceeded, damage to IC chips, microprocessor failure, and/or measurement
inaccuracies due to condensation on the various PC board runners may result.
Effective humidity control is the responsibility of the user.
The CR5000 is not hermetically sealed. Two half unit packets of DESI PAK
desiccant are located by the batteries. A dry package weighs approximately 19
grams and will absorb a maximum of six grams of water at 40% humidity and
11 grams at 80%. Desiccant packets can be dried out by placing the packets in
an oven at 120°C for 16 hours (desiccant only, not the CR5000).
Campbell Scientific offers two enclosures for housing a CR5000 and
peripherals. The fiberglass enclosures are classified as NEMA 4X (water-tight,
dust-tight, corrosion-resistant, indoor and outdoor use). A 1.25" diameter
entry/exit port is located at the bottom of the enclosure for routing cables and
wires. The enclosure door can be fastened with the hasp for easy access, or
with the two supplied screws for more permanent applications. The white
plastic inserts at the corners of the enclosure must be removed to insert the
screws. Both enclosures are white for reflecting solar radiation, thus reducing
the internal enclosure temperature.
The Model ENC 12/14 fiberglass enclosure houses the CR5000 and one or
more peripherals. Inside dimensions of the ENC 12/14 are 14"x12"x5.5",
outside dimensions are 18"x13.5"x8.13" (with brackets); weight is 11.16 lbs.
The Model ENC 16/18 fiberglass enclosure houses the CR5000 and several
peripherals. Inside dimensions of the ENC 16/18 are 18"x16"x8¾", outside
dimensions are 18½"x18¾"x10½" (with brackets); weight is 18 lbs.
1.2 Power Requirements
The CR5000 operates at a nominal 12 VDC. Below 11.0 V or above 16 volts
the CR5000 does not operate properly.
The CR5000 is diode protected against accidental reversal of the positive and
ground leads from the battery. Input voltages in excess of 18 V may damage
the CR5000 and/or power supply. A transzorb provides transient protection by
limiting voltage at approximately 20 V.
System operating time for the batteries can be determined by dividing the battery
capacity (amp-hours) by the average system current drain. The CR5000
typically draws 1.5 mA in the sleep state (with display off), 4.5 mA with a 1 Hz
sample rate, and 200 mA with a 5 kHz sample rate.