CR200/CR200X Series Dataloggers - Campbell Scientific
CR200/CR200X Series Dataloggers - Campbell Scientific
CR200/CR200X Series Dataloggers - Campbell Scientific
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Section 4. Sensor Support<br />
When a pulse channel is configured for pulse input mode, an internal 100 kΩ<br />
pull-up resistor to +5 Volt on the P_SW input is automatically employed. This<br />
pull-up resistor accommodates open-collector (open-drain) output devices for<br />
high-frequency input. An external 100 kΩ pull-up resistor connecting Battery+<br />
to P_LL, C1, or C2 must be added to perform pulse counting on any of those<br />
channels (See Multiple Switch Closure Measurements p. 112).<br />
The maximum input voltage on P_SW is 4 volts. For C1 and C2 the maximum<br />
input voltage is 6.5 volts.<br />
4.4.1.2 Low-Level AC (P_LL)<br />
Rotating magnetic pickup sensors commonly generate AC output voltages<br />
ranging from millivolts at low rotational speeds to several volts at high<br />
rotational speeds. Channel P_LL contains internal signal conditioning hardware<br />
for measuring low-level AC output sensors. P_LL measure signals ranging<br />
from 20 mV RMS (±28 mV peak) to 14 V RMS (±20 V peak). Internal AC<br />
coupling is incorporated in the low-level AC hardware to eliminate DC offset<br />
voltages of up to ±0.5 V.<br />
4.4.2 Pulse Input on Digital I/O Channels C1–C2<br />
Read More! Review digital I/O channel specifications in Specifications p. 35.<br />
Review pulse counter programming in CRBASIC Help for the PulseCount ()<br />
instruction.<br />
Digital I/O channels C1 – C2 can be configured to measure pulse input signals.<br />
Pulse input signals require external 100 kΩ pull-up resistors to be connected<br />
between Battery+ and the control ports. Maximum input voltage level is 6.5 V.<br />
If pulse inputs greater than +6.5 V need to be measured, external signal<br />
conditioning must employed. Contact <strong>Campbell</strong> <strong>Scientific</strong> for further<br />
information.<br />
Low-level AC signals cannot be measured directly on channels C1 – C2.<br />
4.5 Period Averaging Measurements<br />
The <strong>CR200</strong>(X) can measure the period of a signal on any single-ended analog<br />
input channel (SE 1 - 5). The specified number of cycles are timed with a<br />
resolution of 70 ns, making the resolution of the period measurement 70 ns<br />
divided by the number of cycles chosen.<br />
Cycles are counted as the input voltage transitions from less than 0.9 volts to<br />
more than 2.1 volts. The maximum input voltage must be less than 4 volts. The<br />
maximum frequency that can be detected is 150 kHz.<br />
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