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6 USING THE PIU
6.1 Checking the battery charge state
Whilst the PIU is in its powered down state, a short press on the F3 button, will cause the unit to
display it s battery charge state on the D2 scale for several seconds, before returning to its off
state.
6.2 Turning the Unit On
Press F1 for three seconds or more and then release. The unit will then commence its power up
sequence that will be completed when all three phase vectors are illuminated completely. The
unit is then ready to use, assuming the PIU has both mobile and GPS connectivity.
NOTE: if the reference phase has been previously set then the unit will remember this and after
a short period following its power cycle, will turn off the phase vectors or display a single vector
if within the proximity of a detectable cable. After powering on the unit, if any of the bars are
blinking, then initialisation of either the GPS or mobile communications is not complete.
6.3 Turning the Unit Off
Press F1 and F2 together for more than three seconds and release. This will cause the unit to
start its power down sequence which will turn off all LED indications when completed. The unit
will actually be put into a low power sleep mode and will only completely turn off when the
battery charge state is below the minimum required. If this happens it may take up to 20
minutes to reacquire the GPS position.
6.4 Setting the Reference Phase
If the unit has had its reference phase cleared, either by the battery becoming discharged or
being cleared by the user, then all three phase vectors will be illuminated. The Reference Phase
must be set. In order to set the reference phase, the unit must be in communication with the
Remote Reference Unit and have a GPS lock.
Hold the PIU close to a single-phase powered item (e.g. substation fuse holder, lighting switch
etc.), where the phase of the powered item is known. The E-Field signal level (D1) should be
showing near to a maximum signal level. Wait for 20 seconds and then briefly press F2. The unit
should respond by leaving only the vertical phase vector illuminated. If the unit does not turn
off the other phase vectors then this indicates that the unit has been unable to identify a single-
phase field free of interference from other phases. In this case, the user should repeat the
procedure or set the phase at a different location.
NOTE: If the known phase corresponds to the phase vector being displayed (e.g. Red phase or
L1), then the reference phase will not need to be rotated (as described in the section 6.5).
6.5 Rotating the Reference Phase
With the reference phase set but the unit is displaying the incorrect phase vector, Press and hold
F2 for three seconds or more, then press F3 briefly and release, then release F2. The unit will
respond by rotating the phase vector clockwise (or anti-clockwise when in anti-clockwise phase
rotation mode), to the next phase vector. Repeating this procedure will rotate to the next phase
vector and so on.