Logixpro Dual Compressor Exercise 2 -

She did the only thing left. She slammed the emergency stop on Atlas, sprinted to the auxiliary air dryer bypass valve, cracked it open to vent a tiny amount of stored air (counterintuitive, but it reduced backpressure), and then reset Atlas’s overload.

For six years, the system had run on a simple lead-lag routine: Titan ran all day, Atlas kicked in only when the pressure sagged below 95 PSI. It was dumb, but it worked. Until the heatwave.

Maria’s mind flashed to the exercise rubric: “When a compressor faults, the alternate must take over within 2 seconds. Pressure must not fall below 80 PSI.”

That Tuesday, the thermometer on the mezzanine read 104°F. Titan’s cooling fan seized at 2:17 PM. By 2:22, its discharge temperature alarm screamed red on the control panel. The compressor didn't stop—it just kept churning, heating the air to 190°F, expanding it like a furious ghost. The pressure at the receiver tank began to drop. logixpro dual compressor exercise 2

When the maintenance crew finally replaced Titan’s fan at 4:00 PM, Maria collapsed into a rolling chair. On the HMI, the pressure trend showed a near-perfect line at 88 PSI, with only one brief dip to 81.5 PSI.

In the LogixPro simulation, you had ladder logic timers: T4:0 for the “minimum run time” and T4:1 for the “anti-cycle delay.” Maria had no time to program. She had to become the PLC.

She hit start again.

“Atlas, you’re up,” she whispered, hammering the HMI start button.

At 2:30, Maria Chen, the shift electrician, pulled up the LogixPro simulation on her laptop—the training software she’d mastered years ago. But this wasn’t a classroom exercise. This was Exercise 2 for real.

In LogixPro’s “Dual Compressor Exercise 2,” the goal was simple: maintain 90–100 PSI with two compressors, handle duty cycling, and prevent both from running simultaneously for too long to avoid overload. The twist? A random “fault” could disable one compressor, forcing the other to handle the load within strict time limits. She did the only thing left

Atlas roared to life. Pressure stabilized at 96 PSI. For thirty seconds, Maria breathed. Then the production line kicked into high gear—three cappers firing at once, a purge cycle on the filler, and a labeler changeover. The pressure cratered to 85 PSI.

The plant floor at Apex Bottling was a cathedral of stainless steel and hydraulic hiss, but its heart was pneumatic. Two massive air compressors, Titan and Atlas, squatted in the corner, responsible for breathing life into the filling heads, capping machines, and labeling jets. If the air pressure dropped below 90 PSI, the entire line screeched to a halt. If it dropped below 80 PSI, safety interlocks would fire, locking the plant down entirely.

She jumped to the control cabinet, fingers flying over the old Allen-Bradley pushbuttons. She disabled the automatic lead-lag and forced Atlas into continuous run. Then she saw the problem: Atlas’s unloader solenoid was sticky. The compressor was starting under full load, drawing 300% amperage. The thermal overload relay clicked once, twice—on the third click, it would trip. It was dumb, but it worked

Maria stared at the LogixPro window still open on her laptop. The virtual pressure gauge was steady at 95 PSI. The virtual “Dual Compressor Exercise 2” completion banner flashed green.