HART for Schneider Electric
Highway Addressable Remote Transducer - hybrid analog+digital protocol for process field instruments.
Protocol Overview
Highway Addressable Remote Transducer - hybrid analog+digital protocol for process field instruments.
When to Use HART
Choose HART for process instrument integration, upgrading analog systems, or when remote configuration and diagnostics are needed without new wiring.
Technical Specifications
Physical Layer
- Physical Layer: FSK over 4-20mA
- Cable Type: Standard 4-20mA wiring
- Topology: Point-to-point, Multidrop
- Power Over Cable: Yes
Data Layer
- Data Link: Master/Slave
- Encoding: FSK (1200 Hz / 2200 Hz)
- Error Detection: Parity and checksum
- Frame Size: Variable
Performance
- Scan Time: 2-8 updates per second
- Deterministic: No
- Real-Time: No
Certification
- Certification Required: Yes
- License Cost: FieldComm Group membership
- Version: HART 7
Advantages & Disadvantages
Advantages
- ✓Works over existing 4-20mA wiring
- ✓Backward compatible with analog systems
- ✓Extensive device diagnostics
- ✓Remote configuration
- ✓Process and status information
- ✓Huge installed base
- ✓No additional wiring needed
- ✓Intrinsically safe capable
Disadvantages
- ✗Very slow (1.2 kbps)
- ✗Not suitable for closed-loop control
- ✗Limited to process instruments
- ✗Multidrop loses analog signal
- ✗Communication overhead
Common Use Cases & Applications
Industry Adoption
Supported Message Types
Universal commandsCommon practice commandsDevice-specific commandsSupported PLC Brands
Quick Links
Alternative Protocols
- Foundation Fieldbus
- PROFIBUS PA
- 4-20mA analog
Related Standards
- IEC 61131-3
International standard for programmable logic controller programming languages. Defines 5 programmin...
- IEC 61131 Series
Complete series of international standards for programmable logic controllers covering hardware, sof...
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