Molex SST-PB3-CLX-RLL ControlLogix Profibus DP Module

Description

Product Introduction

The Molex SST-PB3-CLX-RLL is an industrial communication interface card designed to integrate Allen-Bradley 1756 ControlLogix systems directly into Profibus DP networks. Sitting in a standard 1756 I/O chassis slot, this module allows the ControlLogix processor to act as a Profibus DP-V1 Master or Slave, enabling seamless data exchange with field instrumentation, VFDs, and remote I/O drops without needing external protocol converters or third-party gateways.

In legacy plant retrofits, bridging Rockwell automation architectures with Siemens-heavy field networks is a common challenge. Lower-cost external gateways introduce communication latency, adding extra failure points and complicated messaging logic. The SST-PB3-CLX-RLL solves this by mapping Profibus DP device data directly into the ControlLogix I/O memory tree, maintaining determinism and high throughput even across complex multi-vendor process environments.

Key Technical Specifications

Application Scenarios & The “Trench” Experience

Picture this: It’s 03:00 AM on a critical production run, and a packaging line controlled by a ControlLogix L73 processor drops offline with a total field communication failure. The original third-party Profibus gateway module gave up the ghost due to power surges, severing connection to 18 Siemens Sinamics VFDs scattered across the plant floor. The plant is bleeding $12,000 every hour the line stays down. Swapping out the blown gateway for an in-chassis SST-PB3-CLX-RLL card, uploading the saved .ss3 configuration file, and linking the assembly instances directly into RSLogix 5000 restores full VFD speed control in under 30 minutes.

• Automotive Manufacturing Plants: Interfacing Rockwell ControlLogix PLCs with European robotic welding cells operating on Profibus DP networks.
• Water & Wastewater Treatment: Linking Allen-Bradley main controllers to remote field instruments, flowmeters, and valve actuators equipped with Profibus interfaces.
• Chemical & Pharmaceutical Processing: Managing batch processes where field sensors deliver DP-V1 extended diagnostic data to the central ControlLogix PAC.
• Material Handling & Warehousing: Interfacing central warehouse controllers with high-speed automated storage and retrieval systems (ASRS) running legacy Profibus drives.

SST-PB3-CLX-RLL

SST-PB3-CLX-RLL

SST-PB3-CLX-RLL

Transparency SOP: Quality Assurance & Testing

We don’t just ship boxes; we test them on actual Allen-Bradley 1756 ControlLogix racks.

1. Inbound Physical Inspection: Inspection of 1756 backplane pins, DB9 port alignment, component soldering, and original Molex serial labels to rule out counterfeit or damaged units.
2. Backplane & Power-On Diagnostics: Card is seated in an active 1756-A7 chassis powered by a 1756-PA72 power supply to verify clean bootup and status LED initialization (OK, COMM, SYS).
3. Profibus Network Loop Testing: Module is connected via RS-485 to a live Profibus test loop containing VFDs and remote I/O blocks running at 1.2 Mbps and 12 Mbps to confirm zero packet loss.
4. Configuration Upload/Download Verification: Verification that the SST Console utility successfully reads, writes, and stores network .ss3 configuration files via the backplane path.
5. Final QC & Anti-Static Packaging: Module is wiped down, enclosed in an ESD anti-static bag, and packed into custom-molded high-density foam shipping containers.

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

• ⚠️ Do NOT forget to enable line termination at both physical ends of the Profibus segment!If the SST-PB3-CLX-RLL is the first or last node on your DB9 trunk cable, make sure the switch on the Profibus connector is flipped to ON. Leaving the line unterminated will cause reflections, leading to random node dropouts that disappear and reappear unpredictably.
• ❗ Watch out for memory mapping limits in Studio 5000!The SST card maps Profibus I/O into the ControlLogix controller tags via Input/Output array structures. If your Profibus network configuration exceeds the card’s maximum backplane transfer size (up to 496 bytes input / 496 bytes output per block), data will get truncated. Always check your byte count in the SST Console before writing your ladder logic.
• ⚠️ Verify GSD file revisions before updating device configurations.When adding a new Profibus slave device, ensure the exact GSD file matching the device’s hardware and firmware revision is imported into the SST Console software. Importing a generic or outdated GSD file will cause the SST module to flag a Configuration Error (CFG ERR) and refuse to establish Class 1 data exchange.

Frequently Asked Questions (FAQ for Conversion)

Q: Is the SST-PB3-CLX-RLL a direct replacement for the older SST-PB3-CLX module?

A: Yes. The -RLL variant is the updated version featuring improved backplane processing, support for RLL (Relay Ladder Logic) memory structures, and broader compatibility with modern Studio 5000 firmware environments.

Q: Does this module require an external 24VDC power supply?

A: No. The module derives all necessary operating power directly from the 1756 ControlLogix chassis backplane power supply.

Q: Can the SST-PB3-CLX-RLL act as both a Profibus Master and Slave simultaneously?

A: Yes. The card supports multi-master topologies as well as simultaneous Master (Class 1/Class 2) and Slave operations, depending on how the channel parameters are configured in the SST Console software.

Q: Is this unit new or refurbished?

A: This unit is New Surplus / Factory Sealed. It comes in its original Molex packaging and has never been installed in an active industrial control cabinet.

Q: What warranty comes with this module?

A: We supply this card with a 12-month full functional replacement warranty. If the unit experiences any hardware failure during normal field operation within one year, we will replace it or issue a full refund.