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 />
Several features give the <strong>CR200</strong>(X) the flexibility to measure many sensor<br />
types. Contact a <strong>Campbell</strong> <strong>Scientific</strong> applications engineer if assistance is<br />
required to assess sensor compatibility.<br />
4.1 Powering Sensors<br />
Read More! See <strong>CR200</strong>(X) Power Supply (p. 53).<br />
The <strong>CR200</strong>(X) is a convenient router of power for sensors and peripherals<br />
requiring a 2.5, 5 or 12 VDC source. It has one program-controlled switched 12<br />
Volt terminal (SW Battery), and two switched voltage excitation terminals<br />
(VX1, VX2). These terminals limit current internally for protection against<br />
accidental short circuits. Sensors can be powered continuously by connecting to<br />
the Battery + terminal, which is the same as connecting sensors directly to the<br />
external battery.<br />
Voltage on the Battery + and SW Battery terminals will changed with the DC<br />
supply used to power the <strong>CR200</strong>(X). The switched voltage excitation terminals<br />
are typically used to supply a brief excitation for a bridge measurement with the<br />
ExDelSE () instruction, but can also be programmed to provide a continuous 2.5<br />
V or 5 V using the Excite () instruction, which is enough to power many<br />
sensors. Switched Unregulated (Nominal 12 Volt) (p. 38) shows the current<br />
limits of SW Battery. Greatly reduced output voltages associated with SW<br />
Battery, VX1, and VX2 due to current limit may occur if the current limits<br />
given in the table in TABLE. Current Sourcing Limits p. 38 are exceeded.<br />
4.1.1 Switched Precision<br />
Voltage (0, 2500, 5000 mV)<br />
Two switched analog output (excitation) terminals, VX1 and VX2, operate<br />
under program control. Check the accuracy specification of these channels in<br />
Specifications (p. 35) to understand their limitations. Specifications are only<br />
applicable for loads not exceeding ±25 mA for 2.5 V excitation, or 10 mA for 5<br />
V excitation. CRBASIC instructions that control excitation channels include:<br />
• ExDelSE ()<br />
• ExciteV ()<br />
4.1.2 Continuous Unregulated (Nominal 12 Volt)<br />
Voltage on the Battery + terminal will change with the <strong>CR200</strong>(X) external<br />
battery voltage.<br />
37
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