HollySys AT4500 Differential Pressure Transmitter Level Gauge

The HollySys AT4500 differential pressure transmitter and level gauge delivers precision measurement for volatile process environments. Engineered with monocrystalline silicon sensor technology, it maintains stable readings despite severe mechanical stress.

Deploying high-pressure instrumentation across vast industrial plants often exposes measurement loops to vibration, thermal shock, and aggressive chemical exposure. Traditional sensors suffer from signal drift and diaphragm fatigue when subjected to continuous pressure fluctuations. The AT4500 differential pressure transmitter solves this challenge by leveraging advanced single-crystal silicon technology and a patented packaging configuration. The sensing element sits physically isolated at the upper section of the metal housing, away from the direct media interface, ensuring both mechanical decoupling and thermal insulation. Glass-sintered integrated leads provide high-strength electrical insulation against the metal body, enhancing resistance to transient voltage surges and electromagnetic interference. This design prevents operational failure in heavy chemical processing and fluid management systems.

Technical Specifications

Range: 0-200Pa～40MPa

Output Signal: 4-20mA+HART @ 24 VDC

Reference Accuracy: ±0.075% of Span Upper Limit

Diaphragm Materials: 316L, Hastelloy C, Tantalum, PFA Coating, Gold-Plated

Process Connection: 1/2-14NPT Female @ Process Interface

Power Supply: 12-45 VDC @ Terminal Block

Ambient Temperature: -40°C - 85°C @ Operational State

Response Time: 90 ms @ Step Input Change

System Integration and Hardware Setup

Proper mechanical installation requires mounting the differential pressure transmitter securely onto a rigid instrument bracket or impulse piping network using rated carbon steel or stainless steel bolts. Connect the process piping to the high and low-pressure chambers, ensuring correct orientation to prevent trapped gas pockets in liquid service or condensate accumulation in gas service. Use shielded twisted-pair cables for signal transmission to minimize electromagnetic interference from nearby variable frequency drives or high-voltage power lines. Terminate the 4-20mA current loop and HART communication wires to the internal screw terminals, taking care to maintain polarity. Ground the cable shield exclusively at the control cabinet end to eliminate ground loops and protect against induced transient surges.

Reliability and Environmental Durability

The enclosure features an IP67 rating, protecting internal electronics against dust ingress and temporary water immersion during washdown cycles. Its rugged aluminum alloy or stainless steel housing resists corrosive atmospheric agents typical of chemical plants and offshore platforms. Integrated thermal compensation circuits adjust for ambient temperature swings, preserving measurement linearity without manual recalibration. The mechanical isolation of the monocrystalline silicon sensor mitigates stress from high pipe-line loads, extending service intervals and lowering overall maintenance overhead across continuous plant operations.

Selection Guidance and Alternative Options

Selecting the appropriate variant depends on the operating medium, static pressure limits, and chemical compatibility requirements of the specific loop. Beijing Zhongping Technology provides comprehensive cross-reference selection support and immediate local stock replacement options to ensure minimal downtime for plant expansions or emergency maintenance events. Engineers should verify the wetted materials, such as selecting Tantalum or Hastelloy C for highly corrosive acids, and confirm flange ratings match existing process connections.

Frequently Asked Questions (FAQ)

1. What is the current local stock status and delivery lead time for urgent replacements?

Beijing Zhongping Technology maintains active regional inventory of standard AT4500 configurations, enabling same-day dispatch for critical maintenance requirements.

2. What is the warranty coverage and RMA procedure for malfunctioning units?

All units include a 12-month manufacturer warranty backed by pre-shipment quality verification, with local RMA processing managed through Beijing Zhongping Technology.

3. What are the electrical supply voltage limits and power consumption characteristics?

The transmitter operates on a loop power supply ranging from 12 VDC to 45 VDC, with typical power consumption optimized for standard 4-20mA loop configurations.

4. Which communication protocols are supported alongside the standard analog output?

The unit supports 4-20mA combined with the HART protocol, as well as Modbus-RTU over RS485 for multi-drop digital network architectures.

5. What environmental protection rating does the housing achieve against dust and moisture?

The assembly meets IP67 standards, shielding internal circuitry from dust ingress and heavy moisture exposure.

6. How is mechanical vibration handled during high-stress industrial applications?

The single-crystal silicon sensor resides in a mechanically isolated upper enclosure, absorbing pipeline vibrations without compromising output stability.

7. What routine maintenance checks are recommended for long-term operational health?

Inspect impulse lines periodically for blockages, verify terminal screw tightness, and check zero-point calibration using a calibrated HART handheld communicator.

8. How does the device integrate with existing control systems and software packages?

Integration utilizes standard HART device description files and Modbus register maps, ensuring seamless compatibility with major distributed control systems and programmable logic controllers.