Instruction Manual

6.4.5 Testing of Manual & Auto Mode :
1. All the parameters can be viewed with the keys on front panel i.e. V, I, W, VA, F.
2. Compare V & I values on display with standard DMM. Also calculate & compareVA & Power
for ( for resistive load power should be equal to VA ).
3. Auto scanning of all parameters can be done by pressing Auto scan / GL key. Auto scanning
is done at speed of 1 Sec. To come out of auto scan mode, press any other key.
6.4.6 Mains Voltage Calibration :
Set mains input voltage to the unit is at 115.0 Volts at 50/60Hz frequency and monitor voltages at
DMM & Power meter simultaneously. Adjust the display to be the same with help of preset VR1
on main board. Check voltages for the range specified ( 75V - 130V ).
6.4.7 Mains Current Calibration :
1. Connect 500mA of load to the system & adjust 0.500A on power meter display with the help
of preset VR2.
Now to calibrate the current throughout the range up to 20A, following procedure is to be
followed.
2. Connect 250mA load physically & switch off the load switch on the meter.
3. To enter software calibration mode, reset the system & press Fkey. After successful eprom
test, systems shows following screen.
CALIBRATION ?
YES = PRESS W KEY
NO = PRES VA KEY
4. If VA key is pressed then the system exists calibration mode & mains voltage in manual mode
is displayed.
5. To go into calibration mode, connect port pin 1.5 ( pin 5 of U2-89S52 ) to ground & press W
key.
6. Go to current mode by pressing I switch. ‘CAL’ message will be displayed along with normal
manual current mode screen.
7. W & VA keys will now function to increase & decrease the display counts respectively.
8. Use standard DMM to get same current on standard meter and on power meter.
9. Press F & AUTO SCAN/GL keys simultaneously to save the calibrated current value & Exit
Software Calibration Mode. The message ‘CALIBRATION SAVED’ will be flashed to confirm
saving.
10. Follow steps from 2 to 9 to calibrate the system on loads of 750mA, 5A & 15A & then verify all
readings.
11. Software Calibration mode will exit automatically without saving changes after 25 sec of idle
operation, it will show following message on display :
CALIBRATION
TIMEOUT