Analysis of the Causes of Abnormal Display in Diffused Silicon Pressure Transmitters

As a key device in industrial process control, abnormal display of the PM-PM200 pressure transmitter is often caused by multiple factors. Based on many years of field service experience, the technical team of Xi'an Shenghongchuang Instrumentation has concluded that common issues with diffused silicon sensors are mainly concentrated in the following three aspects:

1.1 Failure of the Sensor Core Component

After the silicon diaphragm of a diffused silicon piezoresistive sensor is subjected to pressure fluctuations over a long period, the following problems may occur:

• Resistance drift of the Wheatstone bridge exceeds ±0.1%FS
• Medium crystallization causes restricted diaphragm deformation (common in the chemical industry)
• Overpressure shock causes permanent damage to the silicon lattice structure

1.2 Signal Processing Circuit Failure

When transmitters such as OT-1 and OC-1 show display fluctuations, the following should be checked as a priority:

1.3 Installation and Media Compatibility Issues

Models such as SPB-SPB101 may experience the following under special operating conditions:

1. Pulsating flow fields cause measured value oscillation (a damper needs to be installed)
2. Changes in medium viscosity affect response time (such as in petroleum transportation scenarios)
3. Zero drift caused by aging of the sealing ring

Systematic Fault Diagnosis Process

For troubleshooting models such as DLT-DLT200, it is recommended to adopt a three-level diagnostic method:

2.1 Basic Inspection (5-minute Rapid Diagnosis)

Use a multimeter to check in sequence:

• Power loop impedance (should be ≤50Ω)
• Signal line insulation resistance (≥100MΩ/500VDC)
• Ground resistance (≤4Ω)

2.2 Functional Test (Standard Reference Method)

Compare the technical parameters of the FDS-S specification model:

2.3 In-Depth Diagnosis (Professional Equipment Intervention)

When complex faults occur in models such as CHSP-210, the following are required:

1. Use a standard pressure source for full-range calibration
2. Read the internal parameters of the sensor through the HART protocol
3. Conduct a temperature cycle test (-20℃→85℃→25℃)

Key Maintenance Techniques and Preventive Measures

3.1 Correct Calibration Method

Taking the A-10 pressure transmitter as an example, the following should be noted during calibration:

• Preheating time ≥30 minutes (1 hour required for 0.05 accuracy class)
• Use the three-point calibration method (0%、50%、100% range)
• Return error testing is required after calibration

3.2 Key Points for Routine Maintenance

According to the requirements of the 501 pressure transmitter manual:

3.3 System Integration Optimization

When used together with Domestic FZ Series Pipeline Intelligent Electromagnetic Flowmeter, it is recommended to:

1. Uniformly use the MODBUS RTU communication protocol
2. Set the same sampling cycle (500ms recommended)
3. Configure linkage alarm thresholds

Professional Solutions and Technical Support

Xi'an Shenghongchuang Instrumentation provides:

• On-site calibration services for the full range of products such as PH-PH210
• Test reports compliant with GB/T 17614.3-2015
• 7×24-hour remote diagnostic support

Contact our technical team immediately (029-8456XXXX) to obtain the dedicated maintenance tool kit and the latest operating manual for PM-PM200. For complex operating conditions, we can provide a complete flow control system optimization solution including intelligent electromagnetic flowmeter.