Allen-Bradley SST-PFB-SLC Brad / Molex PROFIBUS Module for SLC 500

Description

Product Introduction

The Molex SST-PFB-SLC is an in-chassis PROFIBUS DP communication module designed specifically for the Allen-Bradley SLC 500 platform. Plugging directly into any local or remote 1746 I/O chassis slot, it allows SLC 5/03, 5/04, or 5/05 processors to seamlessly control and monitor PROFIBUS DP field devices—such as Siemens drives, Festo valve manifolds, process transmitters, and remote I/O drops—without requiring external gateways or third-party protocol converters.

Supporting high-speed communication rates up to 12 Mbps, the SST-PFB-SLC acts as a Class 1 Master (DP-V0) or Slave on PROFIBUS DP networks. It bridges field device data straight into the SLC processor’s Input/Output and M0/M1 file data tables, enabling real-time control via standard RSLogix 500 ladder logic.

Key Technical Specifications

Application Scenarios & The “Trench” Experience

A packaging line using an Allen-Bradley SLC 5/05 processor loses communication with a bank of European Festo pneumatic valve islands and Siemens micro-drives on PROFIBUS. The original SST-PFB-SLC card suffers a bus-transceiver failure from a static surge, halting the entire line. Upgrading the PLC architecture to ControlLogix or CompactLogix to get modern network interfaces would require weeks of rewiring and software conversion. Swapping in a replacement SST-PFB-SLC module allows maintenance to restore the PROFIBUS segment in under 20 minutes: drop the card into the 1746 slot, attach the DB9 PROFIBUS cable, download the saved .GSD node mapping using SST Console over the front serial cable, and re-engage the SLC processor.

• OEM Machinery & Packaging Lines: Interfaces A-B SLC controllers with European drives (Siemens, SEW Eurodrive, Danfoss) and pneumatic valve banks.
• Process Skid & Instrumentation Control: Polls PROFIBUS DP flow meters, temperature transmitters, and motor control centers (MCCs) directly into SLC data files.
• Material Handling & Automated Warehouses: Manages PROFIBUS field-bus barcode scanners and photo-eyes across long conveyor lines.
• Retrofit / Migration Projects: Allows legacy SLC 500 systems to co-exist with modern PROFIBUS DP island networks without replacing the main controller.

SST-PFB-SLC

SST-PFB-SLC

Transparency SOP: Quality Assurance & Testing

1. Visual & Hardware Inspection: Inspection of the 1746 backplane connector pins, DB9 serial and PROFIBUS port housings, faceplate clip tabs, and PCB components.
2. Backplane & Power Verification: Inserted into a live 1746-A7 chassis powered by a 1746-P2 power supply to verify boot-up sequence, power consumption, and 4-character scrolling LED status.
3. Configuration Serial Link Audit: Front RS-232 DB9 port connectivity is verified by uploading and downloading .GSD network slave configurations using the SST PROFIBUS Configuration Console.
4. Active Communications Loop Testing:
   • PROFIBUS DP Master Mode: Connected to a live PROFIBUS test rack with ET200S remote I/O drops at 1.5 Mbps and 12 Mbps to verify cyclic IO table updates, token ring rotation, and zero CRC dropouts.
5. Final Cleaning & Packaging: Cleaned, packed in ESD anti-static bags, and protected in custom-cut foam shipping boxes.

The Veteran’s Tech Trap Guide (Crucial Value-Add)

• ⚠️ PROFIBUS DB9 Termination Resistors: Ensure the PROFIBUS connector plugged into the SST-PFB-SLC front DB9 port has the termination switch set correctly (ON if it is an end-of-line node, OFF if daisy-chained through). Improper termination causes intermittent bus dropouts, especially at baud rates above 1.5 Mbps.
• ❗ M0 / M1 Buffer Configuration in RSLogix 500: Simple I/O setups map data to standard Input/Output words (up to 32 words). If your PROFIBUS slave configuration exceeds 32 input/output words, you must configure M0 and M1 file transfer buffers in RSLogix 500. Forgetting to enable M0/M1 buffers will cause truncation of network data.
• ⚠️ Serial Port Cable Warning: The front RS-232 configuration port requires a straight-through DB9 null-modem/serial cable wired specifically for SST module programming. Generic 3-wire serial cables may fail to establish a link with the SST Configuration Console software.
• ❗ GSD File Import Matching: When configuring slave devices in the SST Console, always use the exact .GSD file revision provided by the slave manufacturer. Mismatched GSD configurations will cause the SST-PFB-SLC to report a configuration fault (CFG ERR) and refuse to clear the PROFIBUS master token.

Frequently Asked Questions (FAQ)

Q: Can the SST-PFB-SLC act as both a PROFIBUS Master and Slave at the same time?

A: No. The SST-PFB-SLC must be configured operating either as a PROFIBUS DP Class 1 Master (controlling field slaves) or as a PROFIBUS DP Slave (reporting to another master PLC).

Q: What software is needed to configure the SST-PFB-SLC?

A: Network configuration and GSD file mapping are performed using the Windows-based SST PROFIBUS Configuration Console. Data mappings are then saved directly to the non-volatile memory on the SST module.

Q: Is the SST-PFB-SLC compatible with all SLC 500 processors?

A: It is compatible with SLC 5/03, SLC 5/04, and SLC 5/05 processors. It cannot be used with fixed SLC 5/01 or 5/02 processors due to backplane memory addressing limitations.

Q: What is the maximum distance supported on the PROFIBUS network port?

A: Distance depends on the configured baud rate: up to 1,200 meters at 9.6 Kbps, down to 100 meters at 12 Mbps using standard PROFIBUS Type A shielded twisted-pair cable.

Q: What warranty is provided on surplus or reconditioned SST-PFB-SLC modules?

A: All New Surplus and fully reconditioned SST-PFB-SLC modules include a full 12-month replacement warranty from the invoice date.