Chapter 174: Grounding and Undercurrents

At 7:40 on Tuesday morning, dew still clung to the iron bars of the factory gate. With a shockproof case slung over his back, Lin Chen stepped onto the asphalt, the stiff rubber sole of his shoe digging into his swollen ankle. Every step began with his heel touching down tentatively first; only after confirming there was no stabbing pain did he slowly shift his weight onto his right foot. The worst of the sharp pain had passed, leaving behind a heavy, dull ache, as if his leg had been filled with waterlogged lead. He adjusted his breathing and fixed his attention on the case handle instead. The metal edge bit into his palm, leaving two pale pressure marks.

Old Chen was already waiting at the entrance to Phase Two, a half-smoked cigarette between his fingers. Seeing Lin Chen, he pinched it out and handed over a bottle of mineral water. "You made it? The expert team’s recorders won’t arrive until this afternoon. Get the terminal mounted first. The cable tray and brackets were left ready yesterday."

Lin Chen nodded, ignored the water, and went straight to the reserved spot beside the distribution cabinet. The workshop air was thick with the blended smell of cutting fluid, engine oil, and metal dust. The roar of the stamping press came through two soundproof doors, numbing the soles of his feet with vibration. He set down the case and flipped open the shock latches. The casing of the V3.1 terminal was matte aluminum alloy, half a jin heavier than the previous generation. The wide-input module and SD card slot had already been soldered in place, and the watchdog circuit had its own dedicated power supply. He took out insulating tape, zip ties, a multimeter, and a hydraulic crimping tool, and began to run the wiring.

As he stripped back the insulation on the old grounding wire, his fingers paused. The copper core had already oxidized black, and the cross-section had shrunk by nearly a third. This wasn’t natural aging. The insulation had been soaked in high heat and greasy grime for so long that it had turned brittle and cracked. He looked up at the aging stamping press beside him. A thick layer of oily sludge coated the motor housing, and strands of cotton waste were wound around the cooling fan blades. The voltage fluctuations were only the surface symptom. The real source of interference was right here. Poor grounding meant that every time the machine started or stopped, the surge current could shoot straight into the signal lines. The parsing service wasn’t rebooting because of the power supply—it was the electromagnetic interference tripping the low-level protection logic. He opened the hard-shell notebook he always carried and wrote on a fresh page: Ground resistance exceeds standard. Countermeasure: recrimp terminals, route an independent line to the main grounding bus. Shielding layer needs secondary reinforcement.

He crouched down, unable to bend his left leg completely, so he could only kneel on one knee with his right foot bracing him. He dug out fresh copper lugs and insulating sleeves from the toolbox. Strip the wire. Fit the terminal. Crimp it down. Every movement was slow, but every step followed industrial standards exactly. The workshop wasn’t particularly hot, yet the shirt on his back was already soaked through. Sweat slid down his spine and dripped onto the antistatic mat, spreading into a small dark blot. The swelling in his left ankle began to creep upward, and the muscles in his calf twitched uncontrollably. He stopped, drew a deep breath, and fished two ibuprofen tablets from his pocket, swallowing them dry. The pills scraped his throat on the way down, bitter all the way. He could not stop. The seventy-two-hour countdown began the instant the system powered on.

At 11:20, the new grounding wire was finally connected. Ground resistance on the multimeter: 3.2 ohms—within standard. He closed the terminal’s power switch, and the screen lit up. Self-check passed. [INFO] System boot. V3.1_Release_Tue. He opened the serial debugging tool and hooked up the data stream. The stamping press started up, the motor roaring. Logs began scrolling across the terminal. [INFO] Sampling... [INFO] Voltage: 218V. Stable. No errors in the first hour. In the second hour, the press ran continuously, and the vibration transmitted through the bracket. The terminal casing hummed faintly in resonance. Lin Chen sat on a plastic stool nearby, his left foot propped on a cardboard box, eyes fixed on the screen. The log occasionally flashed [WARN] Vibration threshold exceeded., but the watchdog and buffering logic held firm without a single break. He pulled up the low-level driver and added one line of moving-average parameters to the filter algorithm. Code wasn’t written in a vacuum. It had to learn how to breathe in grease and vibration.

At two in the afternoon, Old Chen came by with a boxed meal. Lin Chen didn’t take it. "Leave it there," he said. He tore open a packet of compressed biscuits and washed them down with mineral water. His stomach felt hollow, but eating too much would make him drowsy. He needed to stay sharp. The clock in the bottom-right corner of the screen flipped to 14:00. Uptime: 2 hours 40 minutes. Data integrity: 99.87%. He opened his mistake notebook and added another line in the margin: Vibration interference causes sampling jitter. Countermeasure: add moving-average filtering on the software side; widen threshold to ±5%. On the hardware side, add rubber damping blocks under the bracket. Technology was not an ideal curve drawn in a laboratory. It was compromise and redundancy on a workshop floor. He had to teach the system to tolerate imperfection.

At four in the afternoon, the stamping press crew changed shifts. Old Li, one of the operators, walked over and tapped the terminal casing. "Kid, can this metal box really hold up? The last recorder shook apart after two days. Every screw came loose." Lin Chen looked up. "The casing is aluminum. The inside’s been potted with silicone. As long as the grounding is sound, it’ll hold." Old Li grinned, said nothing more, and turned away to hand over the shift. Lin Chen lowered his head to the log again. Suddenly the screen flickered. [ERROR] I2C bus timeout. A communication bus timeout. His brow tightened, and he immediately pulled up the low-level driver log. It wasn’t the power. It wasn’t the vibration. The shielding on the signal cable had been damaged where it bent. Metal debris in the workshop had probably caused a tiny short. He had to rewrap the shielding without interrupting the run.

He rose to his feet, and the moment his left foot touched down, a stab of pain nearly made him stumble. He caught the bracket, steadied himself, and pulled insulating heat-shrink tubing and shielding tape from the shockproof case. He could not cut the power. The power-loss buffer logic would catch it, yes, but repeated triggers would wear down the SD card, and the expert team would be checking the baseline state that afternoon. He had no choice but to work live. His left hand pinched the signal wire while his right used a blade to carefully scrape open the damaged shielding mesh. The workshop was so loud he could not hear his own breathing and had to rely on touch alone. The blade scraped across metal, and a faint resistance came through his fingertips. Holding his breath, he slid the heat-shrink tubing over the damaged section and applied local heat with the hot-air gun. The nozzle pointed at the cable bundle, temperature held at 120 degrees. Three seconds. Five seconds. The tubing contracted and wrapped the damaged spot tight. He tested continuity again with the multimeter. Resistance normal.

The error disappeared from the screen. The log resumed rolling. [INFO] I2C bus recovered. Uptime: 8 hours 12 minutes. Integrity: 99.91%. Lin Chen sat back down on the plastic stool. The sweat on his back had already gone cold and clung to his skin. He unscrewed the bottle cap and took a sip. His throat was dry and tight. Outside the windows, evening deepened, and the workshop’s incandescent lamps came on one after another. Their ghastly white light hit the oil-streaked floor and reflected a mottled patchwork of shadows. He touched the USB drive in his pocket. Inside it were the full V3.1 deployment logs, the stress-test curves, and the hardware retrofit checklist. More than half of the 8,000-RMB advance had already been spoken for—his brother’s medicine, his mother’s blood-pressure pills, his own pain patches—every expense marked with a date. The money had bought him three months of breathing room. Whether that buffer would hold depended on whether the screen in front of him stayed green for the next sixty-four hours.

From the end of the corridor came the crisp sound of leather shoes striking terrazzo. Old Chen’s footsteps drew nearer, accompanied by a hushed conversation: "...the provincial bureau experts came early. They brought calibration instruments and the original ledgers. The baseline data has to be exported before nine."

Lin Chen closed his notebook and pulled the zipper of his windbreaker up to his chin. He glanced at the terminal screen. The green run indicator was blinking with perfect steadiness. Seventy-two hours had only just begun. And the real test was not inside the machine, but in the eyes of the people walking in with spreadsheets and standards. He got to his feet, left foot hanging, right leg bearing the weight, and slowly made his way toward the distribution cabinet. He would have to watch tonight’s night-shift inspection himself.