The Yokogawa ALF111-S50, also cataloged as the ALF111 Foundation Fieldbus Communication Module, operates as a dedicated hardware component for Foundation Fieldbus (H1) data exchange within field control stations (FCS).
Hardware Specifications
Parameter
Specification
Model
ALF111-S50
Brand
Yokogawa
Origin
Japan
Weight
0.4 kg
Dimensions
260 mm x 180 mm x 60 mm
Operating Temp
0 to 50 deg C (Standard industrial range)
Power Consumption
0.5 A or less
Bus Connection
Pressure clamp terminals
Fieldbus Interface
Foundation Fieldbus (H1), 31.25 kbps
I/O Capacity
48 points per segment / 32 devices per segment
FOUNDATION Fieldbus Connectivity and Signal Isolation
The ALF111-S50 serves as the primary gateway for FOUNDATION Fieldbus protocol communication, executing Link Active Scheduler (LAS) and Clock Master functions to manage bus traffic. To maintain electrical integrity, the module provides a withstanding voltage of 1500 V AC between field and system interfaces, as well as between individual channels. This galvanic isolation is required to prevent ground loops and common-mode noise propagation from fieldbus segments into the control station backplane.
Frequently Asked Questions
Q: Does the ALF111-S50 support dual-redundant deployment within a single node?
A: Yes, the architecture allows for dual-redundancy by installing two modules in the same node, ensuring seamless failover capability if the primary communication path is interrupted.
Q: Are there specific termination requirements for the fieldbus segment?
A: The module features built-in terminators integrated directly into the pressure clamp terminals, eliminating the requirement for external termination components on the bus segment.
Field Installation Guidelines
Verify that the control rack is de-energized before mounting the module to prevent electrical damage to the backplane communication pins.
Route fieldbus cabling through designated noise-suppression conduits to prevent electromagnetic interference from high-voltage AC lines.
Ensure wire insertion into pressure clamp terminals is firm; verify that no stray strands are exposed to prevent shorts across the H1 bus.
If implementing dual redundancy, ensure both modules are configured with identical network addresses and firmware versions to avoid synchronization conflicts during runtime.
