Users’ Manual
EDI-53 Series Digital Indicator
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Connect the input signal leads to a precision voltage or current calibration source and apply signal
corresponding to zero and full scale input values alternately. Check the corresponding voltage value on
the display. If a precision calibration source is not available a stable variable voltage or current source
may also be used together with a precision 5 ½ digit Digital Multi-Meter to measure the input signal.
The ‘Zero’ and ‘Full Scale’ calibration values for each version of EDI-53 is given below.
EDI-53P – Potentiometric input.
Input: 0.0000 V Display: (Note down the reading on display, say Z)
Input: 1.9000 V Display: (1.9000 + Z)
±
0.0010 V
EDI-53L – Resistance strain gage bridge Load Cell input.
Input: 0.000 mV/V
Display: (Note down the reading on display, say Z)
Input: 3.000 mV/V
Display: (1.5000 + Z)
±
0.0020 V
EDI-53I – 4 – 20 mA current loop input.
Input: 4.000 mA
Display: (0.2000
±
0.0010) V (note down this figure, say Z)
Input: 20.000 mA
Display: (1.0000 + Z)
±
0.0010 V
Recalibration
If the Full Scale value (i.e. calibration) is outside allowed limits, the indicator needs to be recalibrated.
To recalibrate the indicator, open the back cover by removing the 12 Allen head screws with a 2.5 mm
Allen key. The top PCB is the analogue PCB. Locate the potentiometer marked SPAN. Rotate the brass
screw on the top of the potentiometer to get the desired reading on the display with specified input.
System Zero adjustment
In the above section the non-zero reading, Z, is known as system zero offset. By carrying out system
zero adjustment this offset value is set to zero so that with zero input the display shows 0.0000 V in
VOLTS mode.
When the indicator is in ADC check mode (as discussed above) pressing the key ‘0’ sets the system
offset to zero, i.e. the display shows 0.0000 V with zero input. On pressing the ‘.’ key the zero adjustment
is removed and the actual non-zero system offset voltage, if any, is shown on the display.
To quit the ADC check mode Press ‘ESC’ key once.
Start RTC — Key press ‘DATE/4’
Pressing key ‘DATE / 4’ starts the internal Real Time Clock. The RTC is turned off to prevent the RTC
battery from draining out when the indicator is off. Display will flash
RTC STARTED
to confirm that RTC has been started and revert back to enter test number prompt.
Stop RTC — Key press ‘TIME’
Pressing key ‘TIME’ stops the internal Real Time Clock. Display will flash
RTC STOPPED
to confirm that the RTC has been stopped and revert back to enter test number prompt.
Exit ‘Test mode’
To exit the ‘Test mode’, you can either turn off and turn on the indicator again or you can press “ESC’
from the enter test number prompt. Indicator will restart in the normal measurement mode.
