644 Temperature Transmitter

The 644 Temperature Transmitter is the most versatile temperature transmitter family, designed to reduce complexity and simplify the day-to-day operations of diverse temperature measurement applications. With new and easy-to-use capabilities including advanced diagnostics, safety certification, integral transient protection, and flexible display options, the 644 helps you make better decisions for your process.

Key Features and Benefits

• Flexible form factors: DIN head mount and field mount versions available
• Multi-protocol support: 4-20 mA/HART with selectable Revision 5 and 7, FOUNDATION Fieldbus, or PROFIBUS PA
• Safety certified: SIL 3 capable, IEC 61508 certified by an accredited third-party agency for use in safety instrumented systems (single use 1oo1 for SIL 2, redundant use 1oo2 for SIL 3)
• Enhanced display: LCD display and enhanced display with local operator interface (LOI)
• Integral transient protection for improved reliability
• Enhanced accuracy and stability for confident process control
• Transmitter-sensor matching with Callendar-Van Dusen constants
• Variety of enclosures to suit installation requirements

Sensor Input Options

Single or dual sensor input versions are available for RTD, thermocouple, mV, and ohm inputs. The dual sensor head mount (model code S) and field mount (model code D) versions support HART protocol, while single sensor versions (model code H) are available with HART, FOUNDATION Fieldbus, or PROFIBUS PA output.

Advanced Diagnostics for Predictive Maintenance

• Hot Backup feature: if the primary sensor fails, a second sensor seamlessly takes over to prevent measurement failure
• Sensor drift alert: detects drifting sensors and proactively notifies the user
• Thermocouple degradation diagnostic: monitors the health of the thermocouple loop for predictive maintenance
• Minimum and maximum temperature tracking: records temperature extremes of the process and ambient environment

QR Code Asset Tags

Newly shipped devices include a unique QR code asset tag that enables access to serialized information directly from the device, including device drawings, diagrams, technical documentation, and troubleshooting information. This improves mean time to repair, maintains efficiency, and eliminates the time-consuming process of locating and transcribing nameplates.

Product Certifications

The 644 is available with a wide range of hazardous location certifications including ATEX, IECEx, CSA, FM (USA), China Ex (Intrinsic Safety, Flameproof, Type n), INMETRO, Japan, EAC, and Korea approvals.

Specifications

The 644 meets demanding processing needs by delivering field reliability and advanced accuracy and stability. Contact us for availability of specific model codes and options, or to request the full product data sheet (00813-0100-4728).