Parameter List: Fanuc Ot 900

Many second-hand lathes come with Macro B disabled. Check 903.0 = 1. If zero, set it to 1, and suddenly you can use #100 = #101 + 1 and WHILE [#1 LT 10] DO1.

If you are looking at a Fanuc 0T screen and see a string of zeros and ones starting at 900, you are looking at the DNA of the machine tool builder (MTB) configuration. Unlike standard machining parameters (speeds, feeds, rapid rates), the 900 series usually controls System Options. fanuc ot 900 parameter list

Note: Always write down your current parameters before changing anything. One wrong bit can disable the spindle or cause the machine to freeze on startup. Many second-hand lathes come with Macro B disabled

Here is the logic of the 900 series.

| Bit | Function | |------|-----------| | 7 | Axis 1 (X) servo type: 0 = analog (±10V), 1 = digital serial (FANUC α/β) | | 6 | Axis 2 (Z) servo type | | 5 | Separate detector for X axis (0 = motor encoder only, 1 = scale feedback) | | 4 | Separate detector for Z axis | | 3 | High-gain servo mode (0=off, 1=on) | | 2 | Torque limit enable | | 1-0 | Axis scaling factor (pitch error compensation) | If you are looking at a Fanuc 0T

| Bit | Name | Function (1 = Enabled) | | :--- | :--- | :--- | | 0 | ERS | External Reset | | 1 | MTP | Manual Pulse Generator (handwheel) – Critical for most lathes | | 2 | MFS | Machine Lock Feedrate Skip | | 3 | OPP | Optional Stop (M01) skip | | 4 | INI | Input unit – 0: MM, 1: Inch | | 5 | SW8 | Software limit override | | 6 | SWM | Mirror image | | 7 | PRC | Precision contouring (AI contour control) |

You power on and see ALARM 000 (Emergency Stop). But the real problem is SV0441 (Servo parameter error) or PMC SYSTEM ALARM 20 (PMC RAM parity error). Your battery died, and the 900 parameters are gone. Without the list, you cannot tell the control how many axes or what type of spindles exist.