Yokogawa ALF111-S50 Foundation Fieldbus Communication Module

The Yokogawa ALF111-S50 is a FOUNDATION Fieldbus H1 communication module that manages communication between a control system and connected field devices. It operates as the Link Active Scheduler (LAS), coordinating communication on the fieldbus segment. The module provides four fieldbus ports, supports a transmission rate of 31.25 kbps, and is designed for installation in specified Yokogawa node units and compact field control units.

Hardware Specifications

Communication Function

The ALF111 manages the H1 fieldbus communication schedule as the LAS. It coordinates scheduled communication between compatible field devices and supports the exchange of field data with the control system. Each of its four ports connects to one fieldbus segment, so the segment layout and connected device requirements should be checked during system configuration.

The specified LAS function requires an MTL5995 fieldbus power supply. This requirement should be considered separately from the module's rated current consumption of 0.5 A or less. The supplied data does not establish that the module itself powers the fieldbus segments.

Fieldbus Connections and Termination

The module supports two external connection arrangements:

• Pressure-clamp terminal block: A removable terminal block with built-in terminators that can be switched on or off.
• Terminal board connection: Uses the AKB336 connection cable, with YCB138 terminators mounted on the terminal board.

The /F9S00 option code identifies a pressure-clamp terminal block for the fieldbus, model ATF9S-00. Confirm the terminal arrangement and termination requirements before ordering or replacing the module.

Installation and Compatibility

The ALF111-S50 is specified for installation in the following units:

• ANB10S or ANB10D node units for the ESB bus
• ANR10S or ANR10D node units for the ER bus
• AFF50S or AFF50D compact field control units for FIO
• AFV10S or AFV10D compact field control units for Vnet/IP and FIO

Verify the installed unit model and available module position before replacement. For fieldbus device connection specifications, the supplied reference identifies General Specifications - Model LFS2610, FOUNDATION Fieldbus Communication Package (for ALF111), document number GS 33Q03L60-31E.

Ordering Configuration

The supplied suffix-code information identifies the following configurations:

The supplied ordering table also mentions an ISA Standard G3 option and a basic-type code, but its formatting does not clearly establish the complete code sequence for ALF111-S50. Verify the full ordering code against the original ordering specification before selecting environmental options or accessories.

Frequently Asked Questions

Q: What is the main function of the ALF111-S50?

A: It acts as the Link Active Scheduler for FOUNDATION Fieldbus H1 communication and exchanges field data with connected devices. Each of its four ports connects to a separate fieldbus segment.

Q: Does the ALF111-S50 include fieldbus power and termination?

A: The supplied specifications require an MTL5995 fieldbus power supply for LAS operation. Termination depends on the selected connection arrangement; the pressure-clamp terminal block has built-in switchable terminators, while the AKB336 terminal-board arrangement uses YCB138 terminators.

Q: Which units support the ALF111-S50?

A: The specified installation units are ANB10S/ANB10D, ANR10S/ANR10D, AFF50S/AFF50D, and AFV10S/AFV10D. Confirm the installed unit and the required fieldbus connection configuration before replacement.