[solved] How to obtain the reverse Z value in Postprocessor?

[artisanicview]

Hi. I do work on a postprocessor for an SCM machine and I do need to invert all the "Z" values and I can't find a way to do so. More precisely I do need the positive numbers like Z=20.00 to became Z=-20.00 and the Z=-15.50 to became Z=15.50. How I can invert this values?

[CVH]

Hi,
Plunging into material is then not in the negative direction but in the positive direction ...
This should be possible but it sounds more that your Z actuator is working in reverse.
Most drivers setup let you configure this or you need to swap wires.
As example: I have a negated step count per mm on my Y axis because it is a Moving Bed and not a Gantry setup.
And as it came I had to swap 2 of the 4 wires of my Z stepping motor because plunging had to be moving downwards ...

Re-configuring your setup or swapping wires is more natural or logical unless that diving into material is really upwards.

Have a look at EssiPlasmaMM.js
There the zPosition is registered as:
- ID: "Z"
- always: true
- prefix: "Z"
- decimals: "DEFAULT"
- options: {factor: 10, sign: true}

I presume that a factor of -1 and not forcing the sign (can be omitted) should do the trick.
Remind that anything related to Z should be inverted.
Zsafe of for example +30 must be handled as Zsafe = -30 ...
See GCodeBase.js for an extensive list unless already overruled by your postprocessor.

Do not change this in a standard included postprocessor, this may be overwritten on each update.
Include it in a custom Postprocessor, in your case probably based on SCM.js.
Give your custom Postprocessor a practical and distinguishable filename and displayName.

Regards,
CVH

[artisanicview]

Hi CVH.

Most drivers setup let you configure this or you need to swap wires.

I do use a professional machine, so rewiring things is out of question. Everything needs to be done on post.

Zsafe of for example +30 must be handled as Zsafe = -30 ...

No problem, this is handled by the "SET ZFAST=20.00", parameter in the header of the program.

I do made some adjustments in the post to the zPosition line and looks like this:

Code: Select all

this.registerVariable("zPosition",           "Z",                    true, "Z=", "DEFAULT", "DEFAULT", {factor: -1});

I also tryed:

Code: Select all

this.registerVariable("zPosition",           "Z",                    true, "Z=", "DEFAULT", "{factor: -1}");

but still nothing changed. I do get the same old values, not the reverse ones. Any other ideas?

P.S. Fixed. The working syntax is:

Code: Select all

this.registerVariable("zPosition",           "Z",                    true, "Z=", "DEFAULT", {factor: -1});

[CVH]

Nice that you found it out yourself, wasn't at home.

A variable registration exist indeed of 6 parts at max.
The options object is not mandatory, it is (always) between curly brackets and without quotation marks.

Does this also mean that this is solved:
https://www.qcad.org/rsforum/viewtopic.php?f=74&t=10879

Regards,
CVH

[CVH]

Hi,
I even think there is another way ...

When you define block code like "G1 [X] [Y] [Z]"
Then there are 3 tags that you can add: ! , # and -
(I know, this is a figurative example, QCAD/CAM never combines motions in X/Y with those in Z)

[X!] would mean 'write always even when not changed'.
[Y#] means never include the prefix and write always.
[Z-] will negate the value.

Perhaps this is more practical ...
Off course you don't negate an already negated zPosition registered with a factor -1.

Regards,
CVH