Campbell CURS100 Manuale Utente Scaricare il pdf (Pagina 11)

User Manual

3.1 Differential Measurement

The voltage across the completion resistor is measured with the differential

voltage measurement. Use VoltDiff() for the CRBasic dataloggers (for example,

CR1000, CR5000, or CR9000(X)). Use Instruction 2 for Edlog dataloggers (for

example, CR10X). The differential voltage measurement measures the difference

in voltage between the low and high terminals. The CURS100 connects the

resistor between the high and the low terminals.

3.2 Completing the Current Loop Circuit

As shown in Figure 2-1, the 100 Ω sense resistor in the CURS100 is not connected

to the adjacent ground pin that connects into the datalogger signal ground ( or

AG). Hence, an additional connection must be made in order to complete the

loop. Which is commonly done by connecting the CURS100 L terminal to a

datalogger G (power ground) terminal with a jumper wire (Figure 3-1).

Connecting the L terminal to the adjacent ground ( or G) terminal on the

CURS100 will result in unwanted return currents flowing into the datalogger

signal ground ( or AG) which could induce undesirable offset errors in low-

level, single-ended measurements. The ground ( or G) terminal on the

CURS100 can be used to connect cable shields to ground.

Completing the loop by connecting voltages other than ground is possible as long

as the datalogger voltage input limits are not exceeded. These input limits specify

the voltage range, relative to datalogger ground, which both H and L input

voltages must be within in order to be processed correctly by the datalogger. The

input limits are ±2.5 V for the CR10(X) and ±5 V for the CR800, CR850,

CR1000, CR3000, CR5000, and CR9000(X). Hence, when measuring currents up

to 50 mA with the CURS100, a connection to datalogger ground is necessary in

order for the resulting (50 mA)  (100 Ω) = 5 V signal to comply with the ±5 V

input limits for the CR800, CR850, CR1000, CR3000, CR5000, and CR9000(X)

dataloggers.

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 17 18

Nessun commento

Campbell CURS100 Manuale Utente Pagina 11