Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 7)

CR5000 Overview
OV-3
OV1.1.2 Signal Grounds ( )
The Signal Grounds ( ) should be used as the reference for Single-ended
Analog inputs, Excitation returns, and sensor shield wires.
Signal returns from the CAO and Pulse channels should use the terminals
located on the CAO and Pulse terminal strip to minimize current flow through
the
grounds on the analog terminal strips.
OV1.1.3 Power Grounds (G)
The Power Grounds (G) should be used as the returns for the 5V, SW12, 12V,
and C1-C8 outputs. Use of the G grounds for these outputs with potentially
large currents will minimize current flow through the analog section, which
can cause Single-ended voltage measurement errors.
OV1.1.4 Ground Lug
The large ground lug is used to connect a heavy gage wire to earth ground. A
good earth connection is necessary fix the ground potential of the datalogger
and to send to earth transients that come in on either the G or
terminals or
are shunted to ground via the spark gaps protecting other inputs.
OV1.1.5 Power In
The G and 12V terminals on the unplugable Power In connector are for
connecting power from an external battery to the CR5000. These are the only
terminals that can be used to input battery power; the other 12V and SW-12V
terminals are out only. Power from this input will not charge internal CR5000
batteries. Power to charge the internal batteries (17-28 VDC or 18 VRMS AC)
must be connected to the charger input on the side of the LA battery back.
OV1.1.6 Switched 12 Volts SW-12
The SW-12 terminals provide an unregulated 12 volts that can be switched on
and off under program control.
OV1.1.7 Switched Voltage Excitation (VX)
Four switched excitation channels provide precision programmable voltages
within the ±5 Volt range for bridge measurements. Each analog output will
provide up to 50 mA between
±5 V.
OV1.1.8 Switched Current Excitation (IX)
Four Switched Current Excitation channels provide precision current
excitations programmable within
±2.5 mA for resistance or bridge
measurements.
OV1.1.9 Continuous Analog Outputs (CAO)
Two Continuous Analog Outputs (CAO) with individual outputs under
program control for proportional control (e.g., PID algorithm) and waveform
generation. Each analog output will provide up to 15 mA between
±5 V.