Wiring; Llac To Ttl - Campbell LLAC4 Instruction Manual

4. Wiring

LLAC4 Four-Channel, Low-Level AC Conversion Module
TABLE 2. Control Port Compatibility
Datalogger Input (Hz)
CR1000 400,000
CR3000
CR800 400,000
CR5000 5,000,000
CR23X 2,500
CR200(X) 1,000
CR10X 40
Comparing Table 1 to Table 2 suggests that the CR10X may not be able to read
either type of anemometer in high wind situations. However, all other
dataloggers would be appropriate choices.
Most sensors that have a low-level AC output will have three wires: signal,
reference, and drain. The signal wire should go to P1 – P4 on the LLAC4 and
the reference and drain wires to a
that 12 V be applied to its 12 V terminal and G. This power should come from
the datalogger or the datalogger's power supply.
A low-level AC signal on P1 will be converted to a 0-5 V square wave on the
D1 terminal. D1 can be wired to an appropriate datalogger control port that
can make high frequency measurements.
SENSOR
SIG + P1
REF
DRAIN
DATALOGGER
12V 12V
G G
Control Port D1
G G
FIGURE 2. LLAC to TTL
Control Port Measurement Type
C1,C2... C8 High Frequency
C1,C2,C3,C4 High Frequency
C7,C8 High Frequency
C5,C6,C7,C8 High Frequency
P_LL,P_SW,C1,C2 High Frequency
C6,C7,C8 Switch Closure
on the LLAC4. The LLAC4 also requires
LLAC4
3