Industry News & Updates

The long shutdown is over, the lines are set to run, and the schedule is tight. You hit the master start button - and instead of the smooth hum of automated machinery, your control panel lights up like a Christmas tree.

Restarting a manufacturing or industrial production line after a period of downtime is rarely as simple as flipping a switch. Whether coming back from a planned maintenance break, a seasonal holiday shutdown, or an unexpected delay, the restart phase is notorious for throwing curveballs.

Here are five of the most common "hidden hazards" that plague production restarts and how to handle them.

1. Drives and Power Supplies Failing on Power-Up

One of the most frustrating experiences during a restart is equipment dying the exact moment you turn it on. Variable Frequency Drives (VFDs), servo drives, and industrial power supplies are particularly vulnerable during initial power-up.

• Why it happens: Inrush currents, degraded capacitors, or internal moisture build-up during extended downtime can cause components to short circuit instantly upon receiving full voltage.

• The fix: Implement a staged power-up procedure. Perform visual inspections, measure insulation resistance, and consider controlled bus pre-charging rather than subjecting cold, unconditioned hardware to full line voltage.

2. Unexpected Faults During Commissioning

Even if individual machines worked fine before the shutdown, bringing an entire system back online often reveals unexpected system-level faults. Sensors misalign, pneumatic systems lose calibration, and thermal expansion changes mechanical tolerances.

• Why it happens: Physical shifts, temperature fluctuations in the facility, or minor unrecorded tweaks made right before shutdown create unexpected operational variables.

• The fix: Run a rigorous, multi-point commissioning checklist before attempting full-rate production. Test safety interlocks, run low-speed dry runs, and verify sensor baselines before loading real materials.

3. Dead PLC Batteries (and Lost Memory)

Programmable Logic Controllers (PLCs) are the brains of your automated environment. While many modern systems use non-volatile memory, millions of legacy PLCs still rely on internal lithium batteries to maintain RAM, custom parameters, and real-time clocks during power loss.

• Why it happens: During standard operation, the PLC runs on external power. During a shutdown, the internal battery takes over. If that battery reaches the end of its life while the power is off, the PLC wipes its memory clean - leaving you with an expensive metal brick lacking its program.

• The fix: Make PLC battery checks and replacements a standard part of pre-shutdown maintenance routines. Crucially, always maintain updated, off-site software backups for every controller on the floor.

4. Robot Cells Requiring Recommissioning

Industrial robots don't always pick up right where they left off. After prolonged downtime, robotic cells frequently suffer from lost mastering data, joint brake slippage, or communication handoff errors with surrounding equipment.

• Why it happens: Environmental changes, mechanical settling, or flat encoder batteries can erase home positions and TCP (Tool Center Point) calibrations.

• The fix: Establish a clear robot recommissioning protocol. Zero out joint axes, verify mastering points, and run slow-speed trajectory checks to ensure end-effectors don't collide with tooling or fixtures.

5. Communication Network Faults

Industrial networks (EtherNet/IP, PROFINET, Modbus, Fieldbus) thrive on stability. When an entire factory floor powers down and back up, network nodes can fail to re-establish handshakes, resulting in dropped packets and timing timeouts.

• Why it happens: Loose connectors, unaddressed IP conflicts, faulty switches, or electromagnetic interference (EMI) on startup can break the communication loop between PLCs, HMIs, and remote I/O modules.

• The fix: Utilize network diagnostic tools to map active nodes before initiating production. Systematically isolate non-responsive drops rather than blindly restarting the network.

Smooth Restarts Require Strategy

Unexpected downtime is expensive, but chaotic restarts can be even costlier - leading to damaged tooling, ruined product, and safety hazards. By anticipating electrical, programmatic, and network bottlenecks before flipping the main breaker, maintenance and engineering teams can transition from reactive firefighting to smooth, predictable production.

For reliable automation parts, replacements, and engineering support to keep your restart on track, explore solutions with Ralakde.