DR3702 Digital Pressure Gauge with 4-20mA and RS485

$60,000 in Savings: How DR3702 Solved Our Measurement Errors

Our plant’s hydraulic press had been running reliably for years, but recently it started cycling slower than expected. The pressure gauge showed normal readings, yet parts were consistently out of spec. We suspected a sensor issue until the fault persisted through several recalibrations and replacements.

A 4-20mA loop is a current source, which should be immune to electromagnetic interference (EMI). However, long cables act as antennas, collecting noise that can distort the signal at the PLC input card. In our case, the EMI was causing the pressure readings to drift, leading to the inconsistent part quality.

We decided to investigate further by tracing the data flow from the hydraulic press to the PLC. After reviewing the setup and discussing with our instrumentation team, we realized that a 4-20mA signal might not be sufficient given our factory’s EMI environment. We needed a solution that could reject common-mode noise entirely.

That’s when we discovered the DR3702 Digital Pressure Gauge, which offered both 4-20mA and RS485 output options. The RS485 differential signaling was designed to handle long-distance communication with immunity to EMI, making it ideal for our plant’s conditions.

We installed the DR3702 in place of our old 4-20mA sensor. The new gauge provided real-time pressure data through both interfaces but seamlessly converted the signal to RS485 on its way to the PLC. The immediate effect was a steady, accurate reading that matched the mechanical behavior of our press.

The results were clear: with the DR3702 in place, we saved $60,000 in wasted material and lost production time due to incorrect part quality. Moreover, the non-linear correction feature ensured precise readings across the entire 0-100 bar pressure range, something our previous sensor had struggled with.

Key Specifications

• Output signal: 4-20mA or RS485
• LCD display with backlight
• 5-digit display
• DC24V powered
• Multiple engineering unit display options
• Nonlinear correction
• Active or passive migration
• Durable housing for industrial environments

Is your pressure drift actually sensor failure or just EMI on the 4-20mA loop?

Tags: #DR3702