2 theoretical calibration, 3 digital filtering, 2 theoretical calibration 2.3 digital filtering – Rice Lake SCT-30 User Manual
Page 14
10 SCT-30 Weight Transmitter Manual
2.2
Theoretical Calibration
Theoretical calibration may be carried out with or without load cells
connected to the instrument. The analog output is zero (4 mA for the
4-20 mA output case) when the value read by the cell is 0 mV.
1.
Hold down the control knob and set the selector switch to
FS CAL
within
four seconds. The yellow LED will light.
2.
Release the control knob.
3.
5.000mV
will flash on the first line of the display. Adjust the value by
turning the control knob.
4.
Hold down the control knob for at least three seconds.
5.
Upon releasing the control knob, line two on the display will start flashing.
6.
Adjust the analog output value by turning the control knob.
7.
Hold down the control knob for at least three seconds.
8.
Upon releasing the control knob, the first display line begins to flash again.
Confirm the settings by adjusting the selector switch to NORMAL or change
the values again by repeating the above.
Ensure that the weighing system is not loaded and perform the tare
weight zero setting.
Example:
The weighing system uses four 1000 kg cells with 2 mV/V sensitivity, the 4-20mA
analog output has been selected and you wish to have 20 mA at 2000 kg.
Considering that the instrument provides 5 Vdc supply for the load cells, the cell
full scale value is equal to 2 mV/V x 5 V = 10 mV. Additionally, 2000 kg is equal to
50% of the system full scale (4 x 1000 kg = 4000 kg), therefore, the values to enter
are 50% of 10 mV = 5 mV and 20 mA.
2.3
Digital Filtering
The instrument has a digital filter to reduce the effects of weight oscillation. Set the
DIP switch indicated by FILTER.
For an increased effect (weight more stable) increase the value of the
response time.
Table 2-1. Digital Filtering
DIP SWITCH
Response time
[ms]
Display and serial port refresh
frequency
[Hz]
1
2
3
OFF
OFF
OFF
3
300
OFF
OFF
ON
150
100
OFF
ON
OFF
260
50
OFF
ON
ON
425
25
ON
OFF
OFF
850
12.5 (default)
ON
OFF
ON
1700
12.5
ON
ON
OFF
2500
12.5
ON
ON
ON
4000
10
Note
Note
Note