Campbell CR6 Series, Руководство по эксплуатации продукта

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I/O port will supply 16 VDC to a connected peripheral. The connected peripheral or sensor
may be damaged if it is not designed for that voltage level.
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C or U terminals: can be set low or high as output terminals . With limited drive capacity,
digital output terminals are normally used to operate external relay-driver circuits. Drive
current varies between terminals. See also
Digital input/output specifications (p. 222).
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U terminals: can be configured to provide regulated ±2500 mV dc excitation.
See also Power output specifications (p. 213).
2.3 Grounds
Proper grounding lends stability and protection to a data acquisition system. Grounding the data
logger with its peripheral devices and sensors is critical in all applications. Proper grounding will
ensure maximum ESD protection and measurement accuracy. It is the easiest and least expensive
insurance against data loss, and often the most neglected. The following terminals are provided
for connection of sensor and data logger grounds:
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Signal Ground ( ) - reference for single-ended analog inputs, excitation returns, and a
ground for sensor shield wires.
o
6 common terminals
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Power Ground (G) - return for 3.3 V, 5 V, 12 V, U or C terminals configured for control, and
digital sensors. Use of G grounds for these outputs minimizes potentially large current flow
through the analog-voltage-measurement section of the wiring panel, which can cause
single-ended voltage measurement errors.
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4 common terminals
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Resistive Ground (RG) - used for non-isolated 0-20 mA and 4-20 mA current loop
measurements (see
Current-loop measurements (p. 66) for more information). Also used
for decoupling ground on RS-485 signals. Includes 100 Ω resistance to ground. Maximum
voltage for RG terminal is ±16 V.
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1 terminal
l NOTE:
Resistance to ground input for non-isolated 0-20 mA and 4-20 mA current loop
measurements is available in CR6 data loggers with serial numbers 7502 and greater.
These data loggers have two blue stripes on the label.
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Earth Ground Lug ( ) - connection point for heavy-gage earth-ground wire. A good earth
connection is necessary to secure the ground potential of the data logger and shunt
transients away from electronics. Campbell Scientific recommends 14 AWG wire, minimum.
2. Wiring panel and terminal functions 11