--- title: System parameters/Variables slug: system-parametersvariables docTags: createdAt: 2025-03-17T10:47:47.472Z --- In the RS274/NGC language view, a machining center maintains 5999 numerical parameters. They can be accessed by #1 .. #5999. The specific parameters with a dedicated function are listed in the table below. Other parameters in the range of 1..5999 are free to use in your G-Code program. Some of them have a special function and are read-only; see the table below: \**parameters in italics are read-only* | Parameter Number | Purpose | | ---------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | *1 - 26\** | Used for **parameters **when overriding m-functions.
In the g-code there is e.g.
`M999 X100 S1000`
And you have in your macro.cnc:
:::BlockQuote Sub m999 msg “this is my m999 X=”#24” S=”#19 Endsub :::
Inside the subroutine, the given X and S parameters are at #24 and #19
#1-#26 = A – Z parameter value.
Values are negative -1e10 if not provided with `m999` in this example. | | 27 - 4999 | **Free to use**, note that 4995 – 4999 are used by the tool length measurement function under user button 2.
`Z#4996` safe height for tool measurement above the fixed tool setter.
`x#4997` `y#4998` fixed tool setter position.
`z#4999` chuck height, or zero length tool height, chuck just touches the fixed tool setter at this height.
`Z#4995` is used for the tool setter height for zeroing Z under user button 1. | | 4000 - 4999 | Free to use, **persistent**, see above some of these are used by tool length measurement and zeroing. | | *5001 - 5006\** | Position of X – C, interpreter position = work position | | *5008\** | Current tool number | | *5009\** | Current tool radius | | *5010\** | Current tool Z offset (length + zDelta) | | *5011\** | New tool number during tool change (M6) | | *5012\** | Current tool X offset (X offset + xDelta) | | *5013\** | Current G43 Z offset (Z offset + zDelta) | | *5014\** | Current G43 X offset (X offset + xDelta) | | 5015 - 5050 | Used in tool change sub routine | | *5051 - 5056\** | Probe position X - C in machine coordinates | | *5061 - 5066\** | Probe position X - C in work coordinates | | *5067\** | 1 if the probe is triggered after `G38.2`, 0 otherwise | | *5068\** | Current probe value | | *5069\** | Handwheel counter | | *5070\** | Spindle rate in rev/second | | *5071 - 5076\** | Position of X - C, interpreter position without offsets = machine position | | *5081 - 5086\** | Probe position X - C in joint coordinates | | *5101 - 5106\** | MCA negative limit X - C | | *5111 - 5116\** | MCA positive limit X - C | | *5121 - 5126\** | Home position X - C | | *5131 - 5133\** | TCA negative limit X - Z | | *5141 - 5143\** | TCA positive limit X - Z | | *5150\** | Active kinematics type:
1: Trivial
2: 4\_AX\_ACYLINDER (Y -> A mapping)
3: Virtual C
4 - 17: System reserved
18 - 30: Custom 1 – Custom 12 | | *5151\** | ZHC is active | | *5152\** | 1 if the spindle is on, 0 if the spindle is off. | | *5161 - 5166\** | G28 home X - C | | *5181 - 5186\** | G30 home X - C | | *5190\** | G68 rotation method (0 = off, 1 = on) | | *5191 - 5193\** | G68/G51 rotation point X - C | | *5194\** | G68 rotation angle XY | | *5195\** | G68 rotation angle YZ | | *5196\** | G68 rotation angle XZ | | *5200\** | 0 if G51 scaling is off, 1 if G51 scaling is on | | *5204\** | G51 scaling factor X | | *5205\** | G51 scaling factor Y | | *5206\** | G51 scaling factor Z (always 1.0) | | 5211 - 5216 | G92 offset X - C | | 5220 | Coordinate system number | | 5221 - 5226 | Coordinate system 1 X - C | | 5241 - 5246 | Coordinate system 2 X - C | | 5261 - 5266 | Coordinate system 3 X - C | | 5281 - 5286 | Coordinate system 4 X - C | | 5301 - 5306 | Coordinate system 5 X - C | | 5321 - 5326 | Coordinate system 6 X - C | | 5341 - 5346 | Coordinate system 7 X - C | | 5361 - 5366 | Coordinate system 8 X - C | | 5381 - 5386 | Coordinate system 9 X - C | | *5390\** | Spindle selection 0 = M90, 1 = M91, 2 = M92 | | *5391 - 5393\** | Alternative spindle offset X- Z | | *5394 - 5397\** | Spindle speed max M90 - M93 | | 5230, 5250, 5270, 5290, 5310, 5330, 5350, 5370 | Reserved for rotation coordinate system | | *5380\** | Simulation mode, 0: controller connected, 1: simulation mode | | *5397\** | Running mode, 0: running, 1: rendering
Use e.g. if you have `G38.2` movements in your macro file because during rendering `G38.2` always runs until the given end point which may give incorrect tool measurement results. Always take care that the tool table contains (approx.) correct tool data | | *5398\** | Return value of `dlgmsg` (1 = OK, -1 = Cancel) | | *5399\** | Return value for `M55`, `M56` | | 5401 - 5499 | Tool Z offset (length) for tools 1 - 99 | | 5501 - 5599 | Tool diameter for tools 1 - 99 | | 5601 - 5699 | Tool X offset (for lathe) for tools 1 - 99 | | 5701 - 5799 | Tool orientation (for turning) for tools 1 - 99 | | 5801 - 5899 | Tool X delta due to wear | | 5901 - 5999 | Tool Z delta due to wear | **