71M6521 Demo Board User’s Manual
Page: 66 of 111
© 2005-2009 TERIDIAN Semiconductor Corporation
Revision 2.18
2.4 TESTING THE DEMO BOARD
This section will explain how the 71M6521 IC and the peripherals can be tested. Hints given in this section
will help evaluating the features of the Demo Board and understanding the IC and its peripherals.
2.4.1 FUNCTIONAL METER TEST
This is the test that every Demo Board has to pass before being integrated into a Demo Kit. Before going
into the functional meter test, the Demo Board has already passed a series of bench-top tests, but the
functional meter test is the first test that applies realistic high voltages (and current signals from current
transformers) to the Demo Board.
Figure 2-18 shows a meter connected to a typical calibration system. The calibrator supplies calibrated
voltage and current signals to the meter. It should be noted that the current flows through the CT or CTs that
are not part of the Demo Board. The Demo Board rather receives the voltage output signals from the CT. An
optical pickup senses the pulses emitted by the meter and reports them to the calibrator. Some calibration
systems have electrical pickups. The calibrator measures the time between the pulses and compares it to
the expected time, based on the meter Kh and the applied power.
Figure 2-18: Meter with Calibration System
TERIDIAN Demo Boards are not calibrated prior to shipping. However, the Demo Board pulse outputs are
tested and compared to the expected pulse output. Figure 2-19 shows the screen on the controlling PC for a
typical Demo Board. The number in the red field under “As Found” represents the error measured for phase
A, whereas the number in the red field under “As Left” represents the error measured for phase B. Both
numbers are given in percent. This means that for the measured Demo Board, the sum of all errors resulting
from tolerances of PCB components, CTs, and 71M6521 tolerances was –2.8% and –3.8%, a range that can
easily be compensated by calibration.
Calibrator
AC Voltage
Current CT
Meter
under
Test
Optical Pickup
for Pulses
Cal
ib
rat
ed
O
ut
put
s
P
u
lse
C
ount
e
r
PC