SmartVue Operator’s Manual
10-0004-R13
17
3.7
4-20mA Calibration
To ensure the precise accuracy of the current loop input measurements, the 4-20 mA
current loop input channels can be independently calibrated. With a known 4 mA source
supplied to a current loop input, the raw, unconverted value supplied by the analog-to-
digital convertor can be read and set as the corresponding reference for that current level.
Finally, the raw value read when a 20 mA source is supplied to the same input will
calibrate the current loop input channel range characteristic.
To calibrate a 4-20 mA Current Loop Input
1.
Press
MENU > Configure I/O > 4-20mA Calibration to display the following
screen.
2.
Connect a power supply that delivers 4 mA of current to the 4-20mA current input
you wish to calibrate (4-20mA IN 1 or 2) and then press the
Calibrate 4mA
button to set the measured raw current value as the calibrated reference for 4 mA.
3.
Likewise, set the supply to deliver 20 mA and then press the
Calibrate 20mA
button to set the raw value as the calibrated reference for 20 mA.
4.
Press
OK.
3.8
Logic Thresholds
The logic thresholds define the voltage levels at which a low state will transition to a high
state and vice versa. A threshold level for the six DIO/VIN points on the J2 terminal
block can be configured. Likewise, the quadrature/counter inputs together with the two
frequency outputs (indicated by QENC and FRQ OUT on the terminal block legend) can
also be configured with a particular threshold level.
To adjust the logic thresholds
1.
Press
MENU > Configure I/O > Logic Thresholds.
2.
Enter a value for the
DIO/VIN logic threshold between 0 and 15 volts.
3.
Enter a value for the
QENC/FRQ logic threshold between 0 and 15 volts.
4.
Press
OK.
