Campbell Scientific CR5000 Measurement and Control Module - Manual (Page 31)

Section 1. Installation and Maintenance
1-7
H L
1 2
1
H L
3 4
2
H L
5 6
3
H L
7 8
4
H L
9 10
5
H L
11 12
6
H L
13 14
7
H L
15 16
8
H L
17 18
9
H L
19 20
10
DIFF
SE
H L
21
VX1 VX2 VX3 VX4 CAO1 CAO2 IX1 IX2 IX3 IX4 IXR P1 P2 C1 C2 C3 C4
22
11
G C5 C6 C7 C8 G >2.0V G >0.8V 5V 5V G SDI-12 12V G SDM-C1 SDM-C2 SDM-C3 G 12V G SW-12 SW-12 G
H L
23 24
12
H L
25 26
13
H L
27 28
14
H L
29 30
15
H L
31 32
16
H L
33 34
CONTROL I/O
CONTROL I/O POWER
UP
POWER UP
17
H L
35 36
18
H L
37 38
19
H L
39 40
20
DIFF
SE
m
A B C D E
L G I N O
T U V P R S W
) - (
Spc Cap
1 2
PgUp
ENTER
BSPC
SIT
ESC
PgDn End
Del Ins
Graph
char
3
4 5 6
7
0
CURSOR
ALPA
SN
Logan Utah
ADE IN USA
CR5000 ICROLOGGER
CAUTION
DC ONL
POWER IN
11 - 16 VDC
pc card
status
CS IO
COPUTER RS-232
(OPTICALL ISOLATED)
GROUND
LUG
G 12V
Ground Plane Analog Grounds
1.85A
Thermal fuse
1.5k E20A
To CR5000
Electronics
On/Off
5A Thermal fuse
0.9A
Thermal
fuse
1.85A
Thermal fuse
Batteries
SW12
Control
10µf
Excitation, CAO,
Pulse Counter Grounds ( )
Power Grounds (G)
FIGURE 1.7-1. Schematic of CR5000 Grounds
The 9-pin serial I/O ports on the CR5000 are another path for transients to
enter and damage the CR5000. Communications devices such a telephone or
short-haul modem lines should have spark gap protection. Spark gap
protection is often an option with these products, so it should always be
requested when ordering. The spark gaps for these devices must be connected
to either the CR5000 earth ground lug, the enclosure ground, or to the earth
(chassis) ground.
Tie analog signal
shields and returns to
grounds (
) located in
analog input terminal
strips.
Tie CAO and pulse-counter returns into grounds ( ) in CAO and pulse-counter
terminal strip. Large excitation return currents may also be tied into this ground
in order to minimize induced single-ended offset voltages in half bridge
measurements.
External
Power Input
Tie 5 V, SW-12, 12 V and C1-C8
returns into power grounds (G).
Star Ground at
Ground Lug