The Rosemount 644 is a versatile temperature transmitter designed for industrial process monitoring and control. It accepts signals from compatible temperature sensors, including resistance temperature detectors (RTDs) and thermocouples, and converts them into a signal suitable for transmission to a control system.
Available in different mounting styles and communication protocols, the Rosemount 644 can be configured for a variety of process requirements. Depending on the selected model and options, it supports advanced diagnostics, local configuration, and dual-sensor functions for improved measurement integrity.
Key Features
- Flexible mounting options: Head mount, field mount, or rail mount, depending on configuration
- Multiple communication protocols: 4–20 mA/HART, FOUNDATION Fieldbus, or PROFIBUS PA
- Universal sensor inputs: Supports compatible RTDs, thermocouples, millivolt, and resistance inputs
- Advanced diagnostics: Optional Hot Backup™, Sensor Drift Alert, and thermocouple degradation monitoring
- Transmitter-sensor matching: Callendar–Van Dusen constants help reduce total measurement error
- Local configuration: Optional Local Operator Interface (LOI) for convenient field adjustments
- Safety certification options: SIL-certified configurations are available; confirm the required model and safety architecture
Suitable Applications
- Chemical and petrochemical processing
- Oil and gas facilities
- Power generation
- Refining and fuel processing
- Pharmaceutical manufacturing
- Food and beverage processing
- Industrial heating and cooling systems
- General process temperature monitoring
Technical Highlights & Selection Considerations
- Sensor compatibility: Select the appropriate RTD or thermocouple input based on the sensor type and required measurement range.
- Mounting style: Choose head, field, or rail mount according to installation space, environmental conditions, and maintenance requirements.
- Output protocol: Confirm whether the control system requires HART, FOUNDATION Fieldbus, or PROFIBUS PA.
- Single or dual input: Dual-sensor functionality is configuration-dependent and may not be available with every protocol or mounting option.
- Display and configuration: LCD display and LOI options should be specified when local readout or on-site configuration is required.
- Safety and approvals: Verify hazardous-area approvals, SIL certification, enclosure requirements, and other certifications for the exact ordered configuration.
Frequently Asked Questions
Q1: What is the Rosemount 644 used for?
The Rosemount 644 converts temperature sensor signals into standardized or digital signals for industrial process monitoring and control.
Q2: Which communication protocols does it support?
Depending on the selected model, it supports 4–20 mA/HART, FOUNDATION Fieldbus, or PROFIBUS PA.
Q3: Which temperature sensors are compatible with the Rosemount 644?
It supports compatible RTDs and thermocouples, as well as millivolt and resistance inputs. Check the product documentation for the specific sensor type and configuration.
Q4: Does the Rosemount 644 support dual temperature sensors?
Yes, selected configurations support dual-sensor input. Availability depends on the mounting style and communication protocol.
Q5: Does it have a local display?
An LCD display and a Local Operator Interface are available as options on supported configurations. The LOI enables convenient field configuration without specialized configuration tools.
Q6: Is the Rosemount 644 suitable for safety instrumented systems?
SIL-certified configurations are available under IEC 61508. The required certification and redundancy arrangement depend on the safety function and system design.
