Description

Yokogawa AFS40S Field Control Unit

The Yokogawa AFS40S, also cataloged as the AFS40S Field Control Unit, operates as a dedicated hardware component for executing continuous control, sequence control, and algorithmic computation within CENTUM VP and CENTUM CS 3000 systems. It provides direct electrical execution of control programs and manages real-time data flow between I/O modules and operator interfaces.

Hardware Specifications

Parameter	Specification
Model	AFS40S
Brand	Yokogawa
Origin	Japan
Weight	18 kg (approximate, depends on configuration)
Dimensions	482 mm (W) x 133 mm (H) x 400 mm (D)
OperatingTemp	0 to 50 degC
PowerConsumption	200 VA (AC), 120 W (DC)
ProcessorRedundancy	Dual-redundant CPU with automatic failover
ControlNetwork	Vnet/IP or VL net (redundant configuration supported)
I/O Communication	ESB Bus / ER Bus
Memory	ECC RAM for program execution
Installation	19-inch rack-mountable

Process Control Specifics

The AFS40S supports 4-20 mA HART loop protocol and FOUNDATION Fieldbus / Profibus PA connectivity for digital field devices. Channel-to-channel isolation is implemented to prevent signal interference between adjacent loops. The unit includes cold junction compensation (CJC) for accurate thermocouple readings and ensures that control calculations remain consistent under varying ambient conditions.

Frequently Asked Questions

Q: What is the maximum number of hot-swappable modules supported?
A: The AFS40S supports hot-swap of power supply modules and processor cards without interrupting ongoing control, but the total number of I/O nodes depends on system licensing and configuration.

Q: How is backplane power consumption managed during redundant CPU operation?
A: Each CPU card draws nominal backplane current. During dual-CPU operation, load sharing occurs automatically, and power supplies handle redundancy without exceeding rated limits.

Q: Is firmware upgrade compatible with all existing modules?
A: Firmware updates are compatible with standard AFS40S modules; however, any third-party I/O interface cards must be verified for compatibility.

Field Installation Guidelines

• Install in a 19-inch industrial rack with at least 50 mm clearance around ventilation areas.
• Ensure all rack-mounted modules are securely fastened to prevent vibration-induced faults.
• Connect shielded communication cables for Vnet/IP or VL net interfaces; terminate shields at a single point to ground.
• Maintain separate routing for power and signal cabling to minimize electromagnetic interference.
• Verify proper AC/DC input voltage selection and grounding before energizing the unit.

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems