230-04D3

Access machine parameters

Press MOD key, enter code (if required), select 'Machine Parameters', navigate to general geometry parameters section

On iTNC 530 and TNC 620/640, use the search function in machine parameters (MOD > Search) to quickly find MP1500, MP1510, and MP1520 parameters

Check software limit activation status

Locate MP1500.x for each axis (X=0, Y=1, Z=2, etc.). Verify value is set to '1' (active) if software limits should be enabled, or '0' (inactive) if not used. Confirm this matches machine design intent

Disabling software limits (MP1500.x = 0) removes an important safety feature - only do this if hardware limit switches provide adequate protection

Verify minus software limit values

Check MP1510.x for each axis. Values must be in machine coordinate system (mm or inches). Ensure minus limit represents the most negative position the axis should reach

Software limits are always defined in the machine coordinate system (REF-referenced coordinates), not in workpiece coordinates

Verify plus software limit values

Check MP1520.x for each axis. Values must be greater than corresponding MP1510.x values. Ensure plus limit represents the most positive position the axis should reach

The relationship MP1520.x > MP1510.x must always be true, or the control will generate this fault

Save parameters and restart

After correcting values, exit MOD function which automatically saves changes. Perform a control restart (MOD > System Restart or power cycle) to reinitialize monitoring system

Always document original parameter values before making changes - use MOD > Backup function to save configuration to USB

Check current machine positions

Switch position display to REF (machine coordinate) mode by pressing POS key multiple times until REF is highlighted. Note the current position of all axes in machine coordinates

Use the position display filter function to show only REF coordinates for clearer diagnosis

Compare position to software limits

For each axis, verify: MP1510.x < current REF position < MP1520.x. If any axis position is outside this range, that axis is causing the alarm

Do not attempt to jog axes while this alarm is active - the control will prevent motion

Clear alarm and establish reference

Press CE key to clear alarm. If axes were moved manually (encoders disconnected), perform reference point search for all axes using Manual Operation mode > Ref Point key

On absolute encoders (EnDat with absolute position), reference search may only require moving to read position - check MP1200.x setting

Verify reference point execution

After reference search, confirm REF symbol appears in position display for all axes. Re-check that all axis positions are now within software limits defined in MP1510.x and MP1520.x

If position is still outside limits after proper reference search, the software limit parameters may need adjustment or the reference point may be incorrectly positioned

Access PLC programming environment

Press MOD key, select 'PLC Programming' (may require service password). Open the PLC program list to view active programs (typically in PLCxxx.PLC format)

Modifying PLC programs without full understanding can affect machine safety and functionality - document all original code before changes

Search for position preset commands

In PLC editor, search for commands that write to axis position markers (M4100-M4199 for axis position values, or M4000-M4099 for position preset triggers). Check logic for any unconditional or erroneous writes

Use the PLC search function (CTRL+F in editor) to find marker variables M41xx and M40xx quickly