I started with a ship full of max-level veterans, and I'm just a complete noob.

Late at night, Jiang Ming stayed alone in the 502 confidential compartment, spreading the constant temperature paper tape, spring decay curve and end equivalent resistance records of Furnace No. 3 all over the table, and repeatedly sliding the slide rule between several sets of data.

The ticking of the wall clock echoed through the room. The temperature fluctuation after the third purification expanded to ±0.25 degrees Celsius, and the feedforward correction also continued to rise. The old parameters were being gradually eroded by the aging of the material.

Jiang Ming recalculated the thermal inertia of the silicon carbide rod and incorporated the contact resistance drift into the model. When the calculation reached the high-temperature hysteresis loop, it fell back to its original position. Static calibration could only be corrected by following the changes.

Replacing the springs and copper foil can buy an extra 100 hours, and the feedforward table can suppress the slow drift. However, silicon single crystal growth requires continuous operation, and any furnace disassembly or maintenance will interrupt the complete thermal history.

He put down the slide rule, turned the kraft paper notebook to the bottom of the page, and his gaze fell on the two lines he had written earlier about the high-temperature control system and the cybernetics system. His consciousness then sank into the Record of Human Connections.

The old page unfolds in the darkness, and the nodes of the portrait of European academic giants light up one by one, with the threads of control, communication, stochastic processes, and feedback converging into a new entrance.

Jiang Ming selected the cybernetics node, and the sound of the surrounding clocks faded away. When his vision cleared again, an office filled with manuscripts appeared before him.

Thick curtains blocked out the light, the air was thick with the smell of cigars, calculation papers were scattered around the table legs, and probability formulas on the blackboard stretched all the way to the corner of the wall.

Behind the desk sat an elderly man with disheveled white hair, his oversized coat pressing down on the back of the chair. His gaze, behind his glasses, first swept over Jiang Ming, then fell on the furnace temperature model he had brought.

Norbert Wiener picked up the paper with two fingers, read the hysteresis curve of the silicon carbide rod's temperature rise and fall, then casually grabbed a red pen and crossed it across the middle of the static power meter.

"If you test a furnace once and then expect to trust it for five weeks, with fixed parameters chasing a moving target, this kind of controller will only faithfully repeat old mistakes."

Jiang Ming pushed the third constant-temperature paper tape closer, pointing to the area where the spring creep, the increase in contact resistance, and the aging of the silicon carbide rod had not yet completely separated.

"Current measurements can only observe the overall effect. The mechanical and thermal ends change simultaneously. If the identification process is too slow, the sample will have already experienced a loss of control."

Wiener raised the red pen in his hand, tapping the end of the pen on the gradually expanding ripple, his tone revealing straightforward impatience.

"The system isn't inanimate; it's lying to you."

He got up and walked to the blackboard, drew the furnace body, temperature measuring bridge and actuator with chalk, and then led out two feedback lines from the output, one of which returned to the controller and the other entered the parameter identification stage.

The first loop processes the current temperature difference, and the second loop compares the output changes before and after the disturbance, using the response speed, overshoot amplitude, and decay process to infer the current gain and time constant of the furnace body.

"Don't memorize the old parameters for the furnace. Make the controller ask it again every now and then what its current inertia is and what its gain has become."

Jiang Ming stared at the identification process, quickly wrote down the small step disturbance on the paper, divided the temperature response into steady-state increment and transient process, and then extracted the gain and equivalent hysteresis by two integrators.

After the controller obtains new object parameters, the proportional gain is adjusted in the opposite direction to the furnace gain, the integral time follows the change of thermal inertia, and the differential channel is only responsible for suppressing the deviation of rapid rise.

This structure allows the lookup feedforward to continue to handle most of the reference power, while the adaptive loop continuously corrects the errors caused by table aging, transforming the PID controller from a fixed device into one that changes with the object.

As Viner watched Jiang Ming finish writing the parameter update relationship, he held the cigar in his hand without bringing it to his mouth, then pointed to the right side of the page.

"What are you planning to use for calculations? Relays, gears, or a machine that can't even fit into this room?"

"DC operational amplifier transistor, two sets of integrating capacitors, a diode multiplication network, and polarization relays to select heating and cooling parameters."

Jiang Ming removed the discrete operations required by modern digital computing and replaced them with continuous voltage to represent furnace gain and time constant. The parameter update speed is limited by the RC network to avoid the identification loop chasing measurement noise.

The disturbance signal is periodically sent to the power setpoint by the cam contact. The output change is amplified by the bridge and divided into fast and slow paths. The slow path extracts the thermal inertia, and the fast path estimates the gain. The multiplier then forms a new bias voltage based on this.

When the identification result approaches the safety boundary, the limiting diode will lock the parameter update range, and the original fixed PID will still serve as a backup loop. Any new parameters can only move within the test-permitted range.

After Jiang Ming finished writing the last limiting node, Wiener reached out and flattened the warped manuscript paper, then rechecked the signal direction of the pure analog network.

"You've crammed a set of mathematical ideas into vacuum tubes and capacitors—it's bulky and slow, but it works. That's engineering."

Jiang Ming continued to check the disturbance amplitude, controlling the test signal to always keep it within the process tolerance range, allowing the furnace to expose parameter changes, while avoiding visible impacts on the silicon molten zone.

As the discussion drew to a close, Wiener returned to the table and drew another communication channel outside the control loop with chalk, writing bandwidth, noise, and delay on the same line.

"Feedback needs to transmit messages. Channel bandwidth limits how quickly you can understand the system, while latency determines how valuable these messages are when they arrive. Control and communication have always shared a common framework."

Following this sentence, Jiang Ming wrote down the status information, channel capacity, control delay, and identifiable range. Concepts that were previously scattered between communication and automatic control were now connected by a single information flow.

As he prepared to press further, the office wall receded, the pages of the celestial record closed again, and the ticking of the clock returned to cubicle 502.

Jiang Ming turned on the desk lamp and divided the structural diagram he had brought back into his mind into five parts: disturbance generator, response extractor, parameter updater, limiter, and PID corrector.

He listed the high-stability resistors, paper capacitors, dual triodes, germanium diodes, and polarized relays that could be found in the warehouse, and then broke down the multiplication network into four-quadrant modules that could be individually calibrated.

The resistor network is responsible for proportional servoing, the integral capacitor stores the estimated thermal inertia, and the disturbance injection point is connected after the feedforward bias to ensure that the real response formed by the furnace body and the actuator is identified.

As dawn broke outside the window, Old Sun pushed open the door carrying a thermos and was about to fill the enamel mug with water when his view was blocked by the circuit diagram spread out on the corner of the table.

"This adds several more layers of circuitry; does the furnace have to be tested before it can heat up?"

Jiang Ming pushed the page on the disturbance generator over, letting Lao Sun see how the parameter update voltage readjusted as the spring decayed and the contact resistance changed.

"It tests the furnace every now and then, and adjusts the control parameters accordingly to determine the age of the silicon carbide rods."

Old Sun followed the route for a long time, keeping the thermos bottle in his hand the whole time. In the end, he simply put the bottle down by the wall and turned to get his toolbox.

Jiang Ming wrote the disturbance time constant and the deadline for tomorrow in the upper right corner of the drawing. As long as this simulation network is completed, Furnace No. 3 will be able to cross the boundary of the fixed parameters.

The telephone on the table rang at that moment, and Wu Hanzhang's voice came through the receiver, speaking faster than usual.

"The guidance group just received the complete revised parameter package from the Soviet representative. They are urging the Fifth Academy to finalize the decision as soon as possible. Mr. Qian has already notified all groups to review it overnight."

Jiang Ming held the receiver, looked at the adaptive circuit diagram that had just been completed on the table, and with his other hand he had already pulled over the Fifth Academy's lateral stability correction report.

"Send the parameter package to 502 first, I'll check it tomorrow morning."

Wu Hanzhang paused for a moment on the other end of the phone before adding a sentence.

"Ren Xinmin looked at the aerodynamic data and only said four words: 'Too neat.'"