4 PCM
+
Operation Manual
2.4 Warning Lights and indicators
Output voltage indicated by yellow output voltage
level LEDs.
If no lights are lit the voltage is below 20V.
If the 20V LED is lit, the voltage applied is between
20 – 40V.
If the 40V LED is lit, the voltage applied is between
40 – 60V.
If the 60V is lit the voltage applied is between 60 – 80V.
If the 80V LED is lit the voltage is between 80 – 100V.
Voltage Limit
The Voltage Limit LED indicates that the Transmitter has
reached its 100V output voltage limit. When this happens
the resistance of the pipe or ground connection is too
high. Check all connections to correct this problem.
Warning! If the pipeline being surveyed has coating
that is known to be in good condition, it is probable
that the voltage warning LED’s will illuminate as the
current is increased.
If the 60V/80V/100V lights are illuminated, do not use
excessive voltage or current, as this may result in high
current density through small holidays and coating
defects. This may cause minor corrosion if the transmitter
is left switched on for very long periods.
2.5 Display
The 3 digit DISPLAY displays the 4Hz signal current in
amps that is being delivered onto the pipe.
Transmitter status indicated by the following LEDs:
GREEN
Output OK
RED
Over Temperature
RED
Power Limit
RED
Voltage Limit
Over Temperature
If the transmitter temperature exceeds its recommended
limits it will automatically shut down. Wait until the
transmitter has cooled before you recommence operation.
Power Limit
This LED indicates that the external power supply is
incapable of supplying the demanded power to support
transmission at the selected current. The transmitter has
reached its own power limit.
Switch to a lower current setting until the GREEN Output
OK LED illuminates. Allow a few seconds to settle
between selections.
2.6 Signal Connection
Warning! Appropriate safety procedures must be
followed before removing pipeline CP connection.
Switch the PCM transmitter OFF before handling
connection leads.
Procedure
Disconnect both pipe and anode cables from the
rectifier
Ensure the transmitter is turned off.
Connect the White signal output lead to the pipe
cable.
Connect the Green signal output lead to a
suitable anode cable.
Note: If connections are reversed the current direction
arrow on the PCM Receiver will point in the wrong
direction.
Use an isolated low resistance ground such as a sacrificial
magnesium anode or ground bed.
When connecting to an electrical isolation joint the
other pipe section can often provide a suitable ground
connection.
Care must be taken when using an earth stake as the
resistance is often not low enough. The stake must be
positioned at least 45m (150 feet) from the pipe to ensure
an even current distribution.
Using portable transmitters
In some circumstances, you may have to use a portable
transmitter such as the RD4000T3; RD4000T10 or the
RD7K/8K TX range to produce a stronger locate signal.
For example, the ELF signal from the PCM
+
Transmitter
maybe inadequate when:
The receiver is a very long distance from PCM
transmitter or when.
Locating distribution pipes from buildings where
isolation joints are fitted.
Users can connect the portable transmitter to the
pipeline/network at a test point or isolation joint. You can
use either the direct connection and induction methods
for 8kHz location modes. PCM
+
4Hz measurements can
be taken if the PCM
+
Transmitter is switched on.
Note that when using a portable transmitter, the PCM
+
Tx transmitter must not be set to the LF frequency.
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