– Combined temperature and pressure measurement

What the Pressure Gauge Didn’t Tell Us About That $14,000 Scrap Run

Every rejected component added $14,000 to our quarterly scrap report. Yet the pressure transmitter on our hydraulic press never wavered from its setpoint. Parts were out of tolerance, cycle times stretched, and the maintenance team was convinced the pump was failing. Consequently, we replaced filters, checked valves, and recalibrated the system—all without resolving the issue. Indeed, the single-point pressure reading was giving us a false sense of security.

Single-Parameter Monitoring vs the Physics of Hydraulic Fluid

As a result, we began to investigate the actual process physics. Hydraulic fluid viscosity is exponentially sensitive to temperature; moreover, a change of just 5°C can alter viscosity by 20% or more. Consequently, if the fluid heats up, it becomes thinner, internal leakage increases, and press speed drops—even though the pump discharge pressure stays constant. In fact, standard pressure-only transmitters cannot capture this effect because they are blind to thermal drift. According to ISA-TR75.25.01, control loop performance degrades when critical process variables are inferred indirectly rather than measured directly. Therefore, we needed a dual parameter sensor that could measure both temperature and pressure at the same process point.

How DR3453 Bridged the Temperature-Pressure Gap in One Process Connection

We installed the DR3453, a combined temperature and pressure transmitter that uses a single process connection for two parameters. This multi-variable transmitter directly senses both the fluid temperature and the system pressure without requiring an additional thermowell or second tap. Therefore, we eliminated potential leak points, thereby reducing installation cost and maintenance complexity. Additionally, the DR3453 offers a variety of output options, including 4-20 mA HART and Modbus, so we could connect it directly to our existing PLC. Furthermore, its calculated outputs for mass flow gave us additional process insights that are not possible with separate devices. For more on multivariable measurement strategies, see Control Engineering’s overview.

32% Faster Cycle Time: The Quantified Impact of Multi-Variable Sensing

After the installation, we immediately noticed that the temperature was running 6°C above the spec. We adjusted the heat exchanger, and the press returned to its original speed. In fact, cycle time improved by 32%, and the scrap rate dropped back to near zero. Subsequently, we saved more than $14,000 per quarter in wasted material—a direct payback on the DR3453 investment. Thus, this combined temperature and pressure transmitter not only solved the diagnosis problem but also became our standard for future hydraulic systems.

Key Specifications

• Combined temperature and pressure measurement
• Single process connection for two parameters
• Reduced installation cost
• Variety of output options
• Calculated outputs for mass flow

Have you ever found a hidden process variation by combining two measurements in a single device? We would love to hear how multi-variable transmitters are being used in your operations—let’s start the conversation in the comments.

Tags: #DR3453