DR3702 Digital Pressure Gauge with RS485 and 4-20mA

Why Did Our Hydraulic Press Slow Down Despite Normal Pressure Readings?

Our hydraulic press started cycling more slowly, yet the pressure gauge showed normal readings. Parts coming off the line were out of specification, and our maintenance team spent hours searching for the cause. At first, we suspected a faulty pressure sensor. However, further testing revealed a different problem: electromagnetic interference (EMI) was affecting the 4-20mA signal over a long cable run. The press was operating below the expected pressure, but the PLC could not detect the change reliably.

How EMI Can Affect Long 4-20mA Signal Runs

4-20mA is widely used for industrial pressure measurement because it performs well over long distances. However, long cable runs can still pick up electrical noise from motors, variable-frequency drives, pumps, and other equipment. Poor cable routing, grounding issues, and strong electromagnetic fields can make the problem worse. In our case, the interference caused unstable readings at the PLC input. As a result, our team suspected sensor failures, replaced working components, and spent valuable time troubleshooting the wrong problem. We needed a more robust digital communication method for the pressure signal.

How DR3702 Improved Pressure Signal Reliability

We installed the DR3702 Digital Pressure Gauge and connected its RS485 output to our control system. Unlike a conventional analog signal, RS485 uses differential communication to help reject common-mode electrical noise. This made the pressure data more stable across our long cable run. The DR3702 also provides a 5-digit LCD with backlight, making local readings easy to check in low-light factory conditions. Its DC24V power supply matched our existing infrastructure, so we did not need to redesign the power system. The gauge also supports multiple engineering units and nonlinear correction, helping us maintain accurate readings across the operating range.

From Unstable Readings to Reliable Pressure Data

After installing the DR3702, the pressure readings became stable. Our technicians could finally distinguish actual pressure changes from electrical interference. We also stopped replacing pressure sensors that were still functioning correctly. Within three months, hydraulic press downtime dropped by 20%. Over the following year, reduced troubleshooting, lower component replacement costs, and recovered production time generated more than $15,000 in savings.

Why RS485 Can Be Useful in Noisy Industrial Environments

RS485 can be a practical choice when pressure measurement takes place near motors, drives, pumps, and other sources of electrical interference. Its differential signaling helps the receiver distinguish the intended signal from common-mode noise. This can improve communication reliability in electrically noisy environments. For applications with long cable runs, integrating an EMI resistant pressure gauge with RS485 communication can also reduce dependence on unstable analog readings.

DR3702 Key Specifications

• 4-20mA or RS485 output
• 5-digit LCD display with backlight
• DC24V power supply
• Multiple engineering unit options
• Nonlinear correction
• Durable industrial housing
• Digital RS485 communication for reliable data transmission

Is EMI Affecting Your Pressure Measurements?

When a pressure reading looks wrong, the sensor may not always be the problem. Electrical interference can affect the signal between the sensor and the control system, especially over long cable runs. The DR3702 combines local digital display with 4-20mA and RS485 outputs, giving engineers more flexibility when dealing with demanding industrial environments. Could electrical noise be the hidden cause of your pressure measurement problems?
Learn more about the DR3702 Digital Pressure Gauge and its RS485 communication options.

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