Reference Section > Machines > Advanced Post Processor Settings

Voltage latching lets a plasma cut find its own arc voltage instead of following the voltage set for the process. The cut runs at the height-sensed cut height with height control off, and a little way in TouchCut reads the arc voltage, averages it, and height controls following that measured value.

It removes the need to set a cutting voltage at all, and because every cut measures for itself it copes with the cases where no single number is right for the whole job:

•Bevels - the arc is longer at an angle, so the voltage that holds the right height changes with the bevel angle.

•Compound bevels, and bevels that run off the edge of the plate - conditions a preset voltage cannot describe.

•Electrode wear - the voltage for a given height drifts as the consumable wears, and a measured voltage drifts with it.

In Primecut it is a segment code like any other - see Coding Segments for segment codes in general.

What the machine does with it

Voltage latching is not a mode - it is two ordinary TouchCut height control words placed on one coded segment.

Code	What it does
M61	Height control off. The torch holds the height the initial height sense established.
M62	Measure and latch. From this point TouchCut reads the arc voltage over a short distance, averages it, and switches height control on following that average.

Height control stays off from the M61 until an average has actually been latched, so the torch holds its sensed height through the lead in and through the measuring distance, and only then starts following the voltage it just read. That is deliberate - the measurement only means anything while the torch is being held at the height the height sense established.

Once a carriage is latched it follows the voltage it measured itself and nothing else. The process Voltage and Bevel Voltage values are not used and torch wear compensation is not added - the voltage was just measured with the consumables that are fitted. The bevel angle it was measured at is remembered, so a later change of angle on the same cut is tracked.

A later M61 does not throw the measurement away. It turns height control off, and a following M60 resumes on the voltage measured earlier, which is what makes it safe to drop height control for a moment part way along a cut. Only another M62 measures again.

How far the machine measures over comes from an optional D parameter on the M62. The code Primecut places does not carry one, so the machine uses the sampling distance set on its own plasma tool.

Voltage latching depends entirely on the initial height sense, so the machine has to be set up for it - in particular Fast Detect must be off, and TouchCut will refuse to start a cut containing an M62 while it is on. See Plasma Voltage Latching in the TouchCut7 manual for the machine side: the tool settings, choosing the sampling distance, what the voltage panel shows, and what happens when a measurement fails.

Adding voltage latching in Primecut (Settings under Machines)

It is built out of two codes on one segment, so it is added like any other segment code. Under a cutting or beveling tool's Mid-Path Codes node, click Add segment code and choose Voltage Latching. The code arrives ready to use:

•Start Code of M61 anchored to Lead in start with a zero offset, so height control goes off as the arc is struck.

•End Code of M62 anchored to Cut path start with a zero offset - the end of the lead in - so the arc has settled by the time it is measured.

•Place Automatically off. The code is on the tool, ready to use, but no cut latches until you say so - see Choosing which cuts latch below.

Because both ends are anchored, the latch lands in the same place on every part whatever its size, and Segment Length does not apply - the two anchors decide the coded length. To latch further into the cut instead of at the end of the lead in, give the end anchor a positive End offset, or drag the placed code on the nest. Put it where the torch is settled and cutting normally, not in a corner or anywhere the machine is slowing down.

Where the cutting conditions really change part way along a cut, a second Voltage Latching segment placed further in takes a fresh measurement from there.

Choosing which cuts latch

Like any anchored code, Voltage Latching appears as a tick box in the Mid-Path Codes group of each cutting or beveling process's properties, so a cut can be taken out of latching, or put into it, one cut at a time.

The code arrives with Place Automatically off, so those boxes start out unticked and nothing latches until you ask for it. Turn Place Automatically on for the tool once you are happy with it and every new cut of that tool starts out ticked instead. It only sets how the box starts - a cut you have already answered for keeps your answer.

Rolling voltage latching out to a machine

A machine can be set up for voltage latching in one step rather than tool by tool. On the Machines window, tick TouchCut7 Machine. Primecut lists every cutting and beveling tool of that machine that does not already carry the code, with a tick box each, and adds Voltage Latching to the ones you leave ticked - exactly as if it had been added from the Add segment code menu on each of them.

Cancelling that list unticks TouchCut7 Machine again, because rolling the code out is all the tick does.

It is done once, on the change. Codes you then edit or delete stay as you left them, and unticking TouchCut7 Machine afterwards does not remove anything already placed.

TouchCut6: TouchCut6 speaks the same NC dialect as TouchCut7 but does not understand M62. Leave TouchCut7 Machine unticked for a TouchCut6 machine, and do not put the Voltage Latching code on its tools - nothing in a machine's settings can tell the two apart, so this one is for you to answer.