Description

Yokogawa ALF111-S00 FOUNDATION Fieldbus FF-H1 Interface Module

Configured for deterministic process data exchange in Yokogawa CENTUM VP distributed control systems, the Yokogawa ALF111-S00 (base model ALF111) provides direct physical and electrical interfacing between the FCS backplane and FOUNDATION Fieldbus H1 segments at 31.25 kbps.

Hardware Specifications

Parameter	Specification
Model Brand	Yokogawa ALF111-S00
Origin	Japan
Weight	0.3 kg
Dimensions	127 x 25 x 127 mm
Operating Temp	-40 to 70 degC
Power Consumption	1.5 W @ 24 VDC
Transmission Speed	31.25 kbps
Bus Interface	2-wire FOUNDATION Fieldbus H1
Withstanding Voltage	1500 VAC/min (field to system)
Bus Connection	Pressure clamp terminals with removable terminal block and built-in terminators

FOUNDATION Fieldbus H1 Segment Interfacing

The ALF111-S00 implements FOUNDATION Fieldbus H1 link layer scheduling via Link Active Scheduler capability. Channel operation supports cyclic process data transfer using function block execution synchronized to the macrocycle. Electrical isolation is maintained between field wiring and system backplane to prevent ground loop propagation. Cold junction compensation is not applicable; instead, bus power is supplied externally via an isolated fieldbus power conditioner meeting FF-844 standards.

Frequently Asked Questions

Q: Is the ALF111-S00 hot-swappable?

A: Yes. The module can be replaced online without interrupting other active channels, provided redundancy is configured.

Q: What is the maximum device load per segment?

A: The theoretical limit is 32 devices; practical engineering recommendations restrict loading to 16 devices per segment to maintain voltage margin and scheduling performance.

Q: Does it support redundant operation?

A: Yes. Two ALF111-S00 modules can operate in a redundant pair, with automatic switchover in case of module failure.

Field Installation Guidelines

Mount the ALF111-S00 directly into the designated slot of compatible Yokogawa FCS node units such as AFV30, AFV40, AFV10, or AFF50. Use only shielded twisted-pair Type A cable for H1 segments, maintaining shield continuity to the termination point. Ensure proper grounding at one end only to prevent ground loops. Verify bus polarity before energizing the segment. Install built-in terminators at both physical ends of the bus. Confirm no excessive voltage drop exists along the segment prior to commissioning.

Specifications

• Brand: Yokogawa

Advantages

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