The gap between a glass reactor with a thermocouple and a fully automated pilot system is not as wide as most labs assume — and closing it starts with the sensor already on your reactor lid.
TL;DR — Key Takeaways
- A PT100 resistance temperature sensor with ±0.5 °C accuracy is the foundation of any glass reactor control system. Everything else — thermostats, data logging, recipe automation — builds on that signal.
- Most labs already own the hardware needed for basic digital control. The missing piece is usually integration: connecting the sensor, the thermostat, and the stirrer motor to a common data platform.
- The LabBox by Hitec Zang — integrated into HWS automated reactor systems — packs 10 interfaces into a 222 × 58 × 124 mm unit. It connects directly to circulators, stirrers, scales, pumps, and pH electrodes without custom wiring.
- According to a 2024 industry market analysis, approximately 68% of newly installed glass reactor systems between 2022 and 2024 were equipped with IoT-based control units. The shift is no longer theoretical.
Introduction: The Notebook Problem
Walk into any R&D lab and you will find a glass reactor running a synthesis. Beside it, a paper notebook with handwritten temperature readings taken every 15 minutes. The thermostat holds the jacket at setpoint. The stirrer turns at whatever speed was dialed in that morning. Nobody knows the exact moment nucleation began, because nobody was watching at 2:47 AM when the cooling ramp crossed the cloud point.
This is not a technology problem. The sensors, controllers, and software to automate every one of these measurements have existed for years. The problem is that most labs think of process control as an all-or-nothing investment — either you buy a fully automated system for six figures, or you keep the notebook.
That is a false choice. Digital process control for glass reactors is a spectrum, and the practical starting point is the PT100 temperature sensor that many reactors already have installed. From that single signal, a lab can build toward full automation incrementally — adding data logging, then thermostat feedback, then recipe-driven batch control — without replacing the reactor or rewiring the fume hood.
What Is Digital Process Control for a Glass Reactor?
Digital process control for a glass reactor is the use of electronic sensors, controllers, and software to measure, record, and regulate process variables — primarily temperature, stirring speed, dosing rate, and pressure — in real time, replacing manual observation and adjustment with automated, data-driven operation.
At its simplest, this means a PT100 sensor feeding a digital display so the operator reads process temperature without a mercury thermometer. At its most advanced, it means a compact automation platform managing the entire batch sequence: heating to dissolution, controlled cooling, timed reagent addition, and automated data export — all while the scientist works on something else.
The key distinction from industrial distributed control systems (DCS) is scale. Laboratory and pilot-scale glass reactor control systems are designed for 0.25 L to 100 L vessels, typically operate at atmospheric pressure, and must fit on or beside a reactor frame inside a fume hood. They do not require fieldbus wiring, pneumatic actuators, or dedicated control rooms.
How to Build Process Control Into a Glass Reactor — Step by Step
The path from manual operation to full automation follows a logical sequence. Each step adds capability without invalidating the previous investment.
1. Install a PT100 resistance temperature sensor. The PT100 is the standard temperature measurement device for laboratory glass reactors, defined by IEC 60751. It measures temperature by tracking the electrical resistance of a platinum element — 100 ohms at 0 °C, increasing predictably with temperature. A Class A PT100 delivers ±0.15 °C accuracy at 0 °C. In the HWS system, the PT100 probe inserts through a reactor lid port and feeds a standalone temperature controller or indicator display. This single sensor is the foundation for everything that follows.
2. Connect the PT100 to a digital temperature controller. A standalone controller reads the PT100 signal and provides a digital display with programmable setpoints, alarms, and — in more capable units — PID output to drive a thermostat. HWS offers temperature controllers designed for glass reactor applications, providing accurate regulation and real-time monitoring. At this stage, the operator still sets parameters manually, but the system maintains setpoint without constant attention and sounds alarms if temperature drifts outside limits.
3. Close the loop: thermostat feedback control. Connect the temperature controller’s output to the jacket thermostat (circulator). Now the system reads process temperature via the PT100, compares it to setpoint, and adjusts the jacket fluid temperature automatically. This is a closed-loop control system. The operator defines the target; the controller and thermostat execute it. For simple hold-at-temperature processes, this is often sufficient.
4. Add data logging. Without a data record, process control is invisible. Adding a data logger — whether a standalone unit or a software connection via RS-232 or Ethernet — captures the continuous temperature trace, timestamps, and any alarm events. This historical record is essential for process understanding, troubleshooting failed batches, and meeting documentation expectations for pharmaceutical development (ICH Q8/Q9).
5. Integrate a compact automation platform. This is where the LabBox by Hitec Zang enters the picture. Rather than connecting each device (thermostat, stirrer, pump, pH meter, balance) to a separate controller with its own display, the LabBox connects all of them to a single compact unit with 10 built-in interfaces: 4× RS-232 serial ports, 1× analog input (±10 V / 0–20 mA, 18-bit resolution), 1× PT100 input (–200 to 600 °C, ±0.5 °C, 24-bit resolution), 2× digital outputs (24 V, with PWM capability for valve control), and 2× Ethernet ports supporting OPC-UA and Modbus-TCP.
The LabBox runs LabVision software, which provides process flow diagram visualization, recipe-based batch control (HIBATCH module), automated data logging, and report generation. At 222 × 58 × 124 mm, it mounts directly on the reactor frame — no control cabinet required.
6. Define and run automated batch recipes. With sensors, actuators, and a central platform connected, the final step is writing batch recipes: sequences of temperature ramps, hold periods, dosing steps, and conditional logic (e.g., “if pH drops below 6.5, pause addition”). The LabVision HIBATCH module handles this in a graphical interface. Once a recipe is validated, it runs identically every time — eliminating operator variation and enabling unattended overnight operation.
Manual vs. Standalone Controller vs. Full Automation: What Changes at Each Level
| Capability | Manual Operation | Standalone Controller | Full Automation (LabBox) |
|---|---|---|---|
| Messung der Temperatur | Mercury or digital thermometer, read visually | PT100 → digital display, continuous | PT100 → LabBox, 24-bit resolution, logged |
| Temperature control | Operator adjusts thermostat manually | PID controller drives thermostat automatically | Automated, recipe-programmable ramps and holds |
| Stirring speed | Set once, assumed constant | Set once, assumed constant | Controlled and logged; adjustable within recipe |
| Dosing | Manual addition by syringe or funnel | Manual, with timer reminders | Automated via peristaltic pump or syringe pump |
| Data logging | Handwritten notebook entries | Controller memory (limited) | Continuous, time-stamped, exportable (CSV, PDF) |
| Batch consistency | Operator-dependent | Improved (temperature consistent) | Recipe-defined; identical batch-to-batch |
| Overnight operation | Not practical | Possible for simple holds | Fully supported with alarm and safety interlocks |
| Cost | Lowest (existing equipment) | Moderate (controller + sensor) | Higher upfront; lowest per-batch over time |
The critical insight from this table: the jump from manual to standalone controller is where most labs get the highest return on investment. A PT100, a digital controller, and a thermostat connection cost a fraction of a full automation platform — and they eliminate the most common failure mode in R&D: temperature drift during unattended periods.
Full automation delivers its value at higher batch frequency, during multi-step processes, or when regulatory documentation requirements demand continuous data records.
Counterpoint: When Automation Adds Complexity Without Value
Not every reactor benefits from full automation. Consider these scenarios:
Exploratory screening work. When a chemist is running 20 different conditions in a single afternoon, the overhead of programming recipes for each condition exceeds the benefit. A standalone controller with manual setpoint changes is faster.
Very small scale (< 250 mL). At sub-250 mL volumes, the thermal response is so fast that manual control is often adequate. The cost of a full automation platform is disproportionate to the vessel value.
Single-variable experiments. If the only controlled variable is temperature and the process involves no dosing, no pH control, and no timed additions, a standalone PID controller does everything the process needs.
The decision rule: automate when the process has multiple control variables, when batch-to-batch consistency is a deliverable (not just a nice-to-have), or when someone needs to answer the question “what exactly happened during that batch?” with data rather than a notebook entry.
FAQ: Common Questions About Glass Reactor Process Control
What is a PT100 sensor and why is it preferred for glass reactors?
A PT100 sensor is a resistance temperature detector (RTD) that uses a platinum element with a nominal resistance of 100 ohms at 0 °C. It is preferred for glass reactors because of its high accuracy (±0.15 °C Class A at 0 °C per IEC 60751), excellent long-term stability, and linear response across the –200 °C to +600 °C range. PT100 probes are available in glass-compatible immersion formats that insert through standard reactor lid ports without compromising vessel integrity.
Can I automate an existing glass reactor or do I need a new system?
In most cases, you can retrofit automation onto an existing glass reactor. If your reactor has standard port connections for a temperature probe and your thermostat and stirrer motor have serial (RS-232) or Ethernet interfaces, a LabBox can connect to them directly. The platform is designed as an add-on, not a replacement. HWS also offers turnkey automated reactor systems for labs that prefer a factory-integrated solution.
What data does an automated glass reactor system record?
A fully automated system logs all measured and controlled variables with timestamps: process temperature, jacket temperature, stirring speed, dosing volumes and rates, pH, pressure (if measured), and any alarm events. The LabVision software exports data in standard formats (CSV, PDF reports) suitable for both internal analysis and regulatory documentation. For pharmaceutical process development, this continuous data trail supports ICH Q8-aligned process understanding.
How does process control differ between laboratory and pilot scale?
At laboratory scale (0.25–5 L), thermal response is fast and a single control loop (temperature) often suffices. At pilot scale (10–100 L), thermal lag increases, mixing becomes more critical, and dosing steps have larger consequences. Pilot-scale systems typically require multi-variable control — temperature, stirring, and dosing managed simultaneously — which is where a centralized platform like the LabBox provides its strongest advantage.
What is the LabBox by Hitec Zang?
The LabBox is a compact laboratory automation platform developed by Hitec Zang and integrated into HWS automated reactor systems. Measuring 222 × 58 × 124 mm, it provides 10 built-in interfaces for connecting sensors, circulators, stirrer motors, pumps, balances, and pH electrodes. It runs LabVision software for process visualization, recipe control, and data logging. The LabBox is designed as a cost-effective entry point for labs moving from manual to automated reactor operation.
Conclusion: Start With the Signal, Build Toward the System
Digital process control for glass reactors does not require a facilities renovation or a six-month procurement cycle. It starts with a PT100 sensor, a controller, and a decision to stop writing temperature readings in a notebook.
From that foundation, labs can add thermostat feedback, data logging, and eventually recipe-driven batch automation at a pace that matches their process complexity and budget. The technology is modular by design — the same PT100 signal that feeds a standalone display today feeds the LabBox tomorrow, with no rewiring.
The question for most R&D teams is not whether to digitize reactor control. It is how far along the spectrum to go right now — and that depends on the process, not the trend.
Author Bio Placeholder
Dr. Jürgen Haas, HWS Labortechnik, holds a Doctorate in Chemical Engineering with over 30 years of experience in laboratory glass reactor systems for pharmaceutical process development. Dr. Haas works with R&D and pilot-plant teams across Europe to consult reactor configurations optimized for temperature-sensitive processes including crystallization, distillation, and API synthesis.