ESAB Precision Plasmarc EPP-450 Manuel D'instructions page 54

section 6
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%.
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.
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