ESAB Plasmarc EPP-450, Manual

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section 6 troubleshootinG
6.5 control circuit interface using J1, J4 and J6 connectors
Interface to the EPP-450 control circuitry is made with connectors J1, J4 and J6 on the front panel. J1 has 24 conductors, J4
has 2 and J6 has 10.
J1-P and J1-G provide access to the galvanically isolated transistor output signal indicating an “Arc On” condition. See
Subsection 6.8, Arc Current Detector Circuits. J1-L and J1-J are the inputs for the remote Voltage Reference Signal that
commands the EPP-450 output current Subsection 6.9, Current Control Pot & Remote Vref. J1-R and J1-Z supply 115V AC for
remote controls. See Subsection 6.6, Auxiliary Main Contactor (K3 and K33) & Solid State Contactor Circuits and Subsection
6.10, Pilot Arc Hi/lo & Cut/mark Circuits.
J1-E and J1-F are the input connections for the Emergency Stop function. For Emergency Stop to operate, the Jumper
between TB8-18 and TB8-19 must be removed.
J1-S is the input to K8 that parallels S1 switch contact. When 115V AC from J1-R is fed into J1-S, K8 activates placing the Pilot
Arc in High.
J4-A and J4-B are from an isolated contact on the emergency stop (E-stop) switch. This signal can be used by the plasma
control to indicate the state of the E-stop switch on the power source.
Cut / Mark selection: The power source defaults to Cutting mode when there is no signal fed into J1-C. When 115V AC from
J1-R is fed into J1-C, K11 is activated placing the EPP-450 in the Marking mode. For more details concerning the operation
of K11 and the Cut / Mark modes, refer to Subsection 6.10, High / Low Cut Current Modes and Mark Mode.
High / Low current ranges: The power source defaults to low cutting current range (35-100A) when no signal is fed into
J1-T. High range (50A to maximum current rating) is selected whenever 115VAC is fed into J1-T by connecting J1-R to J1-T.
J6 connects to the water cooler. J6-A and J6-B are 115VAC hot and neutral respectively. This 115VAC activates the contac -
tor for the pump. J6-C and J6-D connect to the flow switch. The flow switch is closed when coolant is flowing. J6-E and
J6-H connect to the coolant level switch. The switch is closed when the coolant reservoir contains sufficient coolant and
it is open when the reservoir is low.
6.4.4 procedure for verifying calibration of digital meters.
Voltmeter
1. Connect a digital meter known to be calibrated to the positive and negative output bus bars.
2. Compare the power source voltmeter reading to the calibrated meter reading. Readings should match within
±0.75%.
Ammeter
1. External to the power source, connect a precision shunt in series with the work lead(s). The best shunt is one with a
value of 100 micro-ohms (50mV / 500A or 100mV / 1000A) and a calibrated tolerance of 0.25%.
2. Use a calibrated 4 ½ digit meter to measure the output of the shunt. The amperage indicated with the external shunt
and meter should match power source ammeter to within 0.75%.