7 cr23x grounding, 1 esd protection – Campbell Scientific CR23X Micrologger User Manual
Page 233
SECTION 14. INSTALLATION AND MAINTENANCE
14-7
CR23X
Panel
+12V
G
FIGURE 14.6-2. Connecting to Vehicle Power Supply
14.7 CR23X Grounding
Grounding of the CR23X and its peripheral
devices and sensors is critical in all
applications. Proper grounding will ensure the
maximum ESD (electrostatic discharge)
protection and the higher measurement
accuracy.
14.7.1 ESD PROTECTION
An ESD (electrostatic discharge) can originate
from several sources. However, the most
common, and by far potentially the most
destructive, are primary and secondary lightning
strikes. Primary lightning strikes hit the
datalogger or sensors directly. Secondary
strikes induce a voltage in power lines or sensor
wires.
The primary devices for protection against ESD
are gas-discharge tubes (GDT). All critical
inputs and outputs on the CR23X are protected
with GDTs (RS-232, CS I/O and 12 Vin do not
have GDTs). The GDTs fire at 150 V to allow
current to be diverted to the earth ground lug.
To be effective, the earth ground lug must be
properly connected to earth (chassis) ground.
As shown in Figure 14.7-1, the power ground
and signal ground are independent lines until
joined inside the CR23X.
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- 024A-L Met One Wind Direction Sensor (30 pages)
- 03001-L R.M. Young Wind Sentry Set (34 pages)
- 03002, 03101, and 03301 R. M. Young Wind Sentry Sensors (40 pages)
- 034A-L WindSet (16 pages)
- 034B-L Met One Windset (34 pages)
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- 05103, 05103-45, 05106, and 05305 R. M. Young Wind Monitors (30 pages)
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- 0871LH1 Freezing Rain Sensor (31 pages)
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- 107-L Temperature Probe (28 pages)
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- 108-L Temperature Probe (30 pages)
- 109-L Temperature Probe (30 pages)
- 109SS Temperature Probe (32 pages)
- 110PV Surface Temperature Probe (32 pages)
- 21108 RF450 Demo Kit (14 pages)
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- 227-L Delmhorst Cylindrical Soil Moisture Block (24 pages)
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