CandCNC DCP-01, Setup And Installation Manual, Page: 18 / 54

4. If your plasma unit does not have an “arc ok” signal jack AND you are NOT
using DCP module you will need the external CT (current transformer). D
:
A.)
B.) one hot leads
C.)
5 If you are using the CandCNC Digital Current Probe (DCP),
6. If you have a plasma unit that DOES have an Arc Good signal or you have the
DCP module
7. chassis
o the
following
Make SURE the cord to the plasma unit is disconnected from
any voltage source.
If you have room inside the unit disconnect of the AC prior or
following the Main switch and slide the wire through the center of the current sense
transformer like a finger through a donut. (for low power plasma units less than 50A
rating you may need to take more than one wrap of the single AC wire through the
center hole)
There are two connections on top of the transformer and the large power
resistor supplied needs to be connected with one lead on each
connection. In addition you need to connect a twisted pair wire between
the two connections and the terminal on the board marked
“ ARC
Good ” (J6). No polarity. The transformer is a current transformer and
forms its voltage across the power resistor. This is an AC voltage that we
rectify and use to trip the Arc Good circuit /relay on the THC Sensor PCB
and use the isolated relay contacts to signal the parallel port and
MACH2/3. A good way to mount the current transformer inside the unit is
to use a plastic cable tie and secure it to a nearby bundle of wires or
bracket.
. you need not hook up
any ARC OK signals. The ARC OK signal is derived from the TORCH AMPS (cut
current) feedback. ARC OK trip point is set in the CUT PROFILES in MACH3. See the
section on installing and calibrating the DCP-01/02 on how to set the ARC OK trip point.
, you do not need to install the Current Transformer and power resistor.
Just make the connection to the Arc OK terminals. Some units provide only relay
contacts; (
“ dry Contacts ” ) For that type of signal the ARC OK inputs are J4 and J5 on
the THC Sensor card.
Note: The term Arc Good is interchangeable with Arc Ok , Arc Xfer and OK
to MOVE.
NOTE: IT is ESSENTIAL that the of the plasma unit have a good
earth ground. Refer to the suggested grounding section of the diagrams
(#####) and provide for a good earth ground close to the table. A safety
ground back to a breaker panel many feet away may be a good ground for
AC frequencies (60hz) but poor for higher frequencies like plasma noise.
Since we are bypassing any high frequency noise to the plasma chassis, if
it has a poor noise ground it can actually put noise back into the tip volts
rather than shunting it away!
c. Make a connection between the locations you have identified that tie
directly to the two leads (workclamp and torch tip) to the two
“ TIP
Volta ” terminals. Make sure that these wires are routed where they
cannot come into contact with hot or moving components. Starting with the
REV 14 THC Sensor card the TIP VOLTS inputs have a polarity. The + side
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