Critical Technical Advantages
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Heartbeat Technology & Diagnostics: This integrated suite allows for continuous health checks of the transmitter during active operation. It is capable of detecting process-related issues, such as plugged impulse lines or changes in the diaphragm seal integrity, which are critical for maintaining measurement accuracy in high-temperature applications.
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SmartBlue Wireless Operation: Using a secure Bluetooth connection, the PMD78B can be configured, monitored, and verified from a distance of up to 15 meters. This significantly increases safety for personnel working with high-temperature processes or instruments located in hazardous, hard-to-reach areas.
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Visual Status Alerts: The device utilizes a color-coded display backlight. In normal operation, the screen is green; if a diagnostic message or fault occurs, the display turns red. This provides immediate, clear feedback to maintenance staff without requiring a handheld terminal.
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Guided Safety Workflows: The onboard software features intuitive wizards that guide users through SIL commissioning and documented proof testing. These step-by-step instructions minimize human error and ensure the instrument meets safety requirements throughout its lifecycle.
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Extreme Temperature Capability: By utilizing capillary diaphragm seals, the sensitive sensor electronics are physically isolated from the process heat. This allows the PMD78B to accurately measure level or flow in media reaching 400°C (752°F), such as hot oil, steam, or molten chemicals.
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High Accuracy and Stability: Despite the challenging temperature conditions, the PMD78B maintains a reference accuracy of up to ±0.075%. This stability ensures consistent batch quality and efficient process control over long periods.
Technical Performance Matrix
| Feature | Details |
| Measuring Principle | Differential Pressure (Metallic Sensor) |
| System Configuration | Diaphragm Seals with Capillaries |
| Accuracy | Up to +/- 0.075% |
| Process Temperature | Up to 400°C (752°F) |
| Differential Pressure Range | Up to 40 bar (600 psi) |
| Static Pressure Limit | Up to 160 bar (2,400 psi) |
| Communication | 4-20 mA HART, Bluetooth |
Primary Applications
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High-Temperature Flow Measurement: Monitoring the flow of hot steam or thermal oils using primary elements like orifice plates in power plants or refineries.
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Level in Pressurized High-Temp Tanks: Measuring the liquid level in reactors or distillation columns where the medium is too hot for direct sensor contact.
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Corrosive or Aggressive Media: Utilizing specialized diaphragm materials (like Tantalum or Monel) to isolate the transmitter from chemically aggressive liquids.
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Safety Instrumented Systems (SIS): Deploying in critical safety loops that require the advanced “Heartbeat” verification to ensure the sensor is functional without a process shutdown.
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Difficult Access Monitoring: Using Bluetooth to check the status of transmitters mounted on tall distillation towers or inside heat-shielded enclosures.
