FAGOR 8055 CNC System Gain Parameter Configuration

The parameter settings of a CNC system directly impact the machine’s accuracy and efficiency. However, many beginners feel overwhelmed by the dense parameter tables. Don’t worry! Today, we’ll use the FAGOR 8055 CNC system as an example and walk you through how to correctly set the gain parameters for the drive connections—improving your machine’s performance with ease!



1. Machine Axis Parameter Settings: Key Fields to Fill

P37 (MAXVOLT)
    •    Formula: 9500 × Max Motor RPM Required by Machine / Rated Motor RPM
    •    Function: Limits the maximum motor voltage to protect the equipment.

P38 (G00 Speed)
    •    Set this according to the machine’s maximum design speed, e.g., 24 m/min.

P42 (MAXFEED) and P43 (JOGFEED)
    •    P42 ≤ P38 (Maximum feed speed should not exceed G00 speed)
    •    P43 is the jog speed, usually set to a medium-high value (e.g., 10000).

⸻

2. Gain Parameter Settings: Proportional Gain is Key

P23 (Proportional Gain)
    •    Formula: P23 = P37 / G00 Speed
    •    Example: If P37 = 8550 and G00 Speed = 24 m/min, then P23 = 356.

P24 (Derivative Gain) and P25 (Feedforward Gain)
    •    Initially set both to 0 during basic tuning; adjust later as needed based on system behavior.

⸻

3. Drive-Side Parameter Settings: Gear Ratio and Current Loop

Gear Ratio and Leadscrew Parameters
    •    NP121 (Motor Output Revolutions): Enter according to mechanical design (e.g., 3 turns)
    •    NP122 (Screw Revolutions): Matches the reduction ratio (e.g., 2 turns)
    •    NP123 (Screw Pitch): For example, 20 mm

Current Loop Parameters
    •    SP20: Default is 9500 (corresponds to max analog voltage)
    •    SP21: Enter motor rated speed (e.g., 2000 RPM)

⸻

4. Tuning Tips: Adjusting Interpolated Axis Error

1. Create a Test Program

Example:
G01 X500 Y500 F1000
Observe the following error on X and Y axes. If the errors differ, adjust P23 (Proportional Gain) to bring them closer.

2. Rigidity Adjustment
    •    Increase Rigidity: Raise P23 and P25 appropriately
    •    Reduce Rigidity: Lower P23 and P25 to prevent mechanical vibrations

⸻

5. Real-World Example: Easy-to-Understand Parameter Setup

Scenario:
Machine max speed: 24 m/min
Gear ratio: 1.5:1
Screw pitch: 20 mm
Motor rated speed: 2000 RPM

Machine Parameters:
    •    P37 = 8550
    •    P38 = 24000
    •    P42 = 5000
    •    P43 = 10000
    •    P23 = 356
    •    P24 = 0
    •    P25 = 0

Drive Parameters:
    •    NP121 = 3
    •    NP122 = 2
    •    NP123 = 20
    •    SP20 = 9500
    •    SP21 = 2000

⸻

6. Notes and Reminders
    •    Interpolated Axis Consistency: Axes involved in interpolation (e.g., X/Y) must have identical parameters to avoid trajectory deviations.
    •    Step-by-Step Tuning: Start with basic settings, then gradually optimize gain parameters based on machining requirements.