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

Servo Press Homing Procedure After Power Loss: Step-by-Step

admin

Power loss during production is one of the most disruptive events on a servo press line. The press loses its absolute position reference and cannot resume production until homing is completed correctly.

## Why Homing Is Required After Power Loss

Modern servo presses use absolute encoders that retain position data through battery backup. However, if the battery is depleted, the encoder cable was disconnected, or the drive experienced a fault that cleared encoder data, the press must re-establish its home position.

Signs that homing is required:
- Press HMI shows "Position Unknown" or "Home Required" alarm
- Slide position display shows dashes or error value
- Press refuses to accept run commands

## Standard Homing Procedure

### Step 1: Safety Check
Before homing, visually confirm slide position. If the slide is at an unknown position, manually jog it to approximately TDC using the inch/jog mode at minimum speed.

### Step 2: Clear Active Alarms
Resolve any active alarms before starting homing. Common alarms that must be cleared first:
- Encoder battery alarm (replace battery first)
- Drive fault alarms
- Safety circuit alarms

### Step 3: Select Homing Mode
On the press HMI, navigate to Setup > Homing or Maintenance > Home Position. Most presses offer:
- **Auto homing**: Press moves to TDC sensor automatically
- **Manual homing**: Operator jogs to TDC, then confirms position

### Step 4: Execute Homing
For auto homing:
1. Confirm slide is clear of tooling
2. Press START on homing screen
3. Press will move slowly to TDC sensor
4. Position is set when TDC sensor activates

For manual homing:
1. Jog slide to TDC using position display
2. Verify TDC sensor LED is active
3. Press CONFIRM/SET HOME on HMI

### Step 5: Verify Home Position
After homing, verify:
- Position display shows 0.00mm (or press-specific TDC value)
- TDC sensor LED is active
- Run one slow test stroke and confirm BDC position matches die shut height

## Common Homing Errors

**Press overshoots TDC sensor**: Reduce homing speed in parameters (typically parameter P-HOME-SPD)
**TDC sensor not activating**: Check sensor wiring and target gap (typically 1-3mm)
**Position drifts after homing**: Check encoder cable shielding and grounding

tom_pressops

Lost home position after power loss happened to me twice in my first year on servo presses. The second time I had the procedure memorized and recovered in 20 minutes. My advice: print the homing procedure and laminate it. Tape it inside the electrical cabinet door. When it happens at 2 AM on a Saturday, you will be glad it is right there.

mike_chen_eng

One thing to add on homing after power loss: if your press has a mechanical TDC pin or hard stop, use it as a secondary verification after electronic homing. We had a case where the TDC sensor target had shifted slightly, so the electronic home was 1.2mm off from true TDC. The mechanical pin caught it immediately.