What is a servo press?

A servo press uses servo motors for precise force and position control during forming operations.

How do I calculate servo press tonnage?

Use our free tonnage calculator at servopress.club/tonnage-calculator.html

Fanuc alarm 414 position error overflow - how to fix?

tony_servo

Fanuc alarm 414 — position error overflow. Cleared it, ran for an hour, came back. What's the actual root cause?

**What Is Alarm 414
**
Fanuc servo alarm 414 means the position error (difference between commanded and actual position) has exceeded the parameter setting. The press stops immediately.

**Parameter to Check
**
The position error limit is set in parameter 1828 (for each axis). Default is often 10,000 pulses. For a servo press with 1μm resolution encoder, 10,000 pulses = 10mm — this is too large for a press application.

Recommended setting: 500-2000 pulses (0.5-2mm) depending on press size.

**Common Causes
**
#**1. Acceleration Too High**

If the press motion profile demands faster acceleration than the motor can deliver, position error builds up and triggers 414.

Fix: Reduce acceleration in the motion profile. Check parameter 1620 (acceleration time constant).

**2. Load Inertia Mismatch
**
If the motor is undersized for the press inertia, it cannot follow the commanded position.

Check: Calculate inertia ratio. Should be below 10:1 for press applications. Above 30:1 will cause 414 alarms.

#**3. Mechanical Binding**

Gib too tight, lubrication failure, or foreign object in the die area causes sudden load increase.

Check: Run press at 10% speed with no die. If 414 clears, the problem is mechanical load.

**4. Servo Gain Too Low
**
If position loop gain (parameter 1825) is too low, the servo cannot correct position error fast enough.

Fix: Increase parameter 1825 by 10% increments until stable.

**Reset**

Fix root cause first. Then: E-stop → release → RESET on operator panel.

anna_plc

On alarm 414, one diagnostic trick: temporarily double the position error limit and see if the alarm goes away. If it does, the motor is just barely exceeding the threshold and you may have a mechanical drag issue (tight gibs, low counterbalance) rather than a drive problem. If the alarm persists even with a wider limit, the encoder or drive has a real fault.

toolndye_dave

One thing not mentioned: alarm 414 can also be caused by a failing encoder. If the encoder skips counts, the position error accumulates until it trips the alarm. Check the encoder signal quality with an oscilloscope before adjusting parameters. If the signal is noisy, replacing the encoder is the fix, not increasing the error limit.

mchen_servo

Dealt with 414 on two different Fanuc setups. Both times the root cause was not what we expected.

First one was a 150T with intermittent 414 after about 45 minutes of running. Turned out the brake was dragging — not fully releasing. Motor had to fight the brake drag, position error slowly accumulated until it tripped. We found it by monitoring the torque command at constant speed. It was 15-20% higher than the sister machine. New brake solenoid fixed it. Total cost: $180 part, 2 hours labor.

Second one was a 300T, alarm 414 only at high speed. Encoder cable was routed next to the VFD power cables for the hydraulic unit. EMI was corrupting the encoder feedback at high motor RPM. Rerouted the encoder cable through a separate conduit with a ferrite choke at the drive end. Never came back.

My diagnostic sequence for 414: check torque command vs baseline first (rules out mechanical drag), then scope the encoder signals (rules out EMI/cable), then check the coupling between motor and ballscrew for backlash. Parameter adjustment should be last resort, not first.

pressroom_tom

Coming back to this — we had another 414 pop up last month on a different press (300T Fanuc, about 5 years old). This time it was purely thermal. The press ran fine for the first 2 hours of the shift, then started throwing 414 intermittently.

Tracked it down to the ball screw thermal growth. As the screw heated up it elongated about 0.04mm, which pushed the slide position just past the error limit at BDC. The fix was simple — we adjusted parameter 2064 (position error limit) from 3mm to 5mm for this press. But the real fix was adding a 15-minute warm-up cycle to the startup procedure. Run 50 empty strokes at half speed before loading the die. The thermal growth stabilizes and the 414 stops.

Point is: if your 414 only shows up after the press has been running a while, think thermal before you think mechanical or electrical. Put a dial indicator on the slide at BDC and watch it over 30 minutes of continuous running. If it drifts more than 0.02mm, that's your answer.