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Table 10-1: Network topology, bit rate, and cable length
1
Bit Rate
(kbps)
1000
500
250
125
50
1
Default Bit Rate is 250 kbps. Change with
10.5 Multiple devices
Multiple GRANITE Measurement Modules may be connected to a single data logger using a
daisy-chain or star topology (see
In both network configurations, as total cable length increases, the maximum possible bit rate
decreases. Limitations on cable length and baud rate are examined in the document
Physical Network Layouts for the CPI Bus
When including two or more TEMP 120 devices in the program, the processing mode of the data
logger affects the measurement timing of each TEMP 120. In sequential mode, the TEMP 120
devices make measurements one after the other, following the order of their instructions within
the program. Conversely, in pipeline mode, the devices start their measurements simultaneously.
Pipeline mode is recommended.
11. Maintenance and calibration
Protect the TEMP 120 from humidity and moisture.
l
Send to Campbell Scientific for factory calibration every three years.
l
If sending the TEMP 120 to Campbell Scientific for calibration or repair, consult first with a
Campbell Scientific representative. If the TEMP 120 is malfunctioning, be prepared to perform
some troubleshooting procedures with Campbell Scientific. Many problems can be resolved with
Maximum total cable length (ft)
Daisy-chain topology
Full termination
50
200
500
1200
2800
CPISpeed()
Connecting multiple GRANITE Measurement Modules
.
Half termination
1
200
400
1000
2400
instruction.
Star topology
No termination
not viable
100
400
1000
2400
(p. 17)).
Designing
TEMP 120
23
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