Overview:
- The system checks for the AC signal via ISO1212
when the relay is open. A normal (unwelded)
condition means there are not any output
pulses.
- The system checks for the AC signal via ISO1212
when the relay is closed. A normal (AC present)
condition means there are no output pulses.
Complete the following work before powering the
TIDA-010239 board.
Connect the AM62_R_ENABLE (pin 36, J2) to
3.3V (TP14_P) to enable the K1 relay at power
up.
- Connect oscilloscope probe 1 to LINE1_IN (TP1_P).
There is no need to connect the probe 1 reference
clip.
- Connect oscilloscope probe 2 to RELAY_CHECK_L1
(J2). Connect the probe 2 reference clip to PGND
(TP7_P).
- Connect oscilloscope probe 3 to RELAY_CHECK_L2
(J2). There is no need to connect the probe 3
reference clip.
- Connect oscilloscope probe 4 to RELAY_CHECK_L3
(J2). There is no need to connect the probe 4
reference clip.
Note:
- The oscilloscope reference clip is tied to
earth GND by default and for this test setup the
reference clip was connected to PGND. This
technically removes the functional isolation of
the circuit but does make the functional testing
easier. If isolated measurement is required, an
isolation transformer can be used to power the
scope.
- RELAY_CHECK_N (J2) can also be checked if
there is more than 4 channels.
Powering the board for measurement:
- Apply an external 12-V (500 mA) power supply to
J1_P so that the relay can be enabled before
turning on the AC line power. This prevents
potential arcing when you enable the relay.
Normally, AC zero crossing detection is required
before operating the relay. In this case, we are
testing with manual relay control.
- With the relay already closed, turn on the AC
line power supply (240 VRMS) and
observe the waveforms on the scope.
- When finished, turn off the AC line power first
before removing the 12-V supply. The backup
supercapacitor can keep the relay closed for a
while even when the AC line power is
disconnected.
- The measurement can be repeated with the relay
open by disconnecting the AM62_R_ENABLE
from 3.3V.