SST SST-PFB-CLX Retrofit PROFIBUS Scanner for Legacy Systems

SST SST-PFB-CLX Retrofit PROFIBUS Scanner for Legacy Systems

The SST SST-PFB-CLX is a PROFIBUS DP master/slave scanner module designed for Rockwell Automation ControlLogix backplane platforms. As legacy PROFIBUS master cards reach end-of-life and original OEM spare parts become increasingly difficult to source, the SST-PFB-CLX provides a proven, retrofit-compatible replacement path for plant engineers managing aging distributed control architectures. Whether you are upgrading a process skid, replacing a discontinued third-party PROFIBUS interface, or extending the operational life of an existing ControlLogix chassis, the SST-PFB-CLX delivers reliable Class 1 master functionality with minimal disruption to existing field wiring and PLC program logic.

The module occupies a single slot in any standard ControlLogix chassis — including the 1756-A4, 1756-A7, 1756-A10, and 1756-A13 backplane sizes — and communicates with the ControlLogix controller via the standard 1756 backplane interface. It supports PROFIBUS DP-V0 and DP-V1 protocols, enabling direct integration with field devices such as Siemens ET 200S distributed I/O stations, ABB AC500 remote I/O, Pepperl+Fuchs segment couplers, and Phoenix Contact PROFIBUS repeaters already installed in the field. Because the SST-PFB-CLX uses a standard GSD-based configuration approach, existing PROFIBUS network topologies, device addresses, and baud rate settings can typically be preserved without rewiring or reconfiguring field instruments.

For facilities running mixed-vendor control environments, the SST-PFB-CLX is particularly valuable during phased migration projects where the PROFIBUS field network must remain operational while the upper-level control layer is being upgraded. Engineers can retain existing Siemens SIMATIC DP slaves, Yokogawa field transmitters with PROFIBUS PA adapters, or Honeywell SmartLine devices on the same physical segment while transitioning the master controller to a modern ControlLogix platform. This approach eliminates the need for a full field rewire and significantly reduces the engineering hours required for I/O remapping.

Upgrade Compatibility Table

Retrofit Planning for Existing Automation Systems

A successful SST-PFB-CLX retrofit begins with a thorough audit of the existing PROFIBUS segment. Before removing the legacy master card, document all slave node addresses, GSD file versions, baud rate settings, and the physical DB9 connector pinout on the existing cable. In most installations, the PROFIBUS cable shield and termination resistors at both ends of the segment must be verified — a common source of communication errors after a card swap. If the existing segment uses a Pepperl+Fuchs OZD Profi repeater or a Phoenix Contact PROFIBUS optical link module to extend cable distance, these devices remain fully compatible with the SST-PFB-CLX and do not need to be replaced.

Inside the ControlLogix chassis, confirm that the 1756-PA72 or 1756-PB72 power supply has sufficient capacity to support the additional module load. The SST-PFB-CLX draws approximately 800 mA from the backplane at 5 VDC. If the chassis is already heavily loaded with 1756-IF16 analog input modules, 1756-OB16E digital output modules, or a 1756-L73 or 1756-L83 controller, a power budget calculation should be completed before installation. In some cases, adding a 1756-A4 expansion chassis with a dedicated 1756-PA72 power supply is the most practical solution for space-constrained control cabinets.

For the software side, the SST-PFB-CLX integrates with Studio 5000 Logix Designer through an Add-On Instruction (AOI) package provided by SST. The AOI maps PROFIBUS I/O data directly into the ControlLogix tag database, preserving the logical structure of the original program where possible. If the legacy system used a Siemens S7-300 or S7-400 as the PROFIBUS master, the GSD files for existing field devices — such as Siemens ET 200M I/O stations, Endress+Hauser Promag flowmeters with PROFIBUS PA adapters, or Yokogawa EJA transmitters — can be imported directly into the SST Configurator without modification. This significantly reduces the time required to rebuild the I/O configuration from scratch.

HMI screens connected to the ControlLogix system via a 1756-ENBT EtherNet/IP bridge or a 1756-EN2T module will continue to read process values from the same controller tags after the PROFIBUS scanner is replaced, provided the tag names and data types are preserved during the AOI import. For facilities using a Rockwell FactoryTalk View SE or FactoryTalk View ME HMI, no screen modifications are typically required if the tag mapping is maintained correctly. A 1784-U2DHP USB-to-DH+ programming cable or a standard Ethernet programming connection to the 1756-EN2T is sufficient for online program verification and final commissioning.

Downtime Control During System Migration

Minimizing unplanned downtime is the primary concern for any PROFIBUS master card replacement on a live production line. The recommended approach is to pre-configure the SST-PFB-CLX offline using the SST Configurator before the scheduled maintenance window. Import all GSD files, assign slave addresses, and verify the I/O data map against the existing program logic. Upload the AOI to the ControlLogix project file and perform a full offline simulation if the controller supports it. This preparation work can typically be completed in four to eight hours, reducing the actual on-machine changeover to a single planned shutdown window of two to four hours.

During the physical swap, power down the ControlLogix chassis using the 1756-PA72 power supply switch rather than removing the controller module, which preserves the program in the controller’s battery-backed memory. Remove the legacy PROFIBUS card, install the SST-PFB-CLX in the same or an adjacent slot, reconnect the PROFIBUS DB9 cable, and restore power. After the controller goes online, download the updated project file, verify that all PROFIBUS slave nodes appear in the SST-PFB-CLX diagnostic table, and confirm that process values are updating correctly in the FactoryTalk View HMI before releasing the line back to production. A pre-tested spare SST-PFB-CLX unit held in local inventory provides an additional safety net and is strongly recommended for critical process applications.

All SST-PFB-CLX units supplied by NINERMAS are pre-shipment tested under powered conditions to verify backplane communication, PROFIBUS port integrity, and firmware version. Each unit ships with a test report and is covered by a 12-month warranty from the date of delivery. Long-term supply commitments and buffer stock programs are available for customers requiring guaranteed availability across multi-year maintenance contracts.

Retrofit Support FAQ

Q1: Can the SST-PFB-CLX directly replace a legacy third-party PROFIBUS master card in my ControlLogix system?
In most cases, yes. The SST-PFB-CLX is designed as a ControlLogix backplane module and replaces any PROFIBUS master function previously handled by a third-party card in the same chassis. The existing PROFIBUS field wiring, slave addresses, and GSD configurations are preserved. The primary change is on the software side, where the SST AOI replaces the legacy driver. Compatibility should be verified against your specific legacy card model and firmware version before ordering.

Q2: What commissioning steps are required after installing the SST-PFB-CLX?
After physical installation, import your existing GSD files into the SST Configurator, map slave I/O data to ControlLogix tags using the provided AOI, download the updated project to the controller, and verify live data from each PROFIBUS slave node. Check PROFIBUS bus diagnostics for any address conflicts or termination errors. Final commissioning typically takes two to four hours for a segment with up to 20 slave devices.

Q3: Is the SST-PFB-CLX compatible with both DP-V0 and DP-V1 slave devices?
Yes. The SST-PFB-CLX supports PROFIBUS DP-V0 and DP-V1 Class 1 master operation, making it compatible with the full range of standard PROFIBUS DP field devices including drives, distributed I/O stations, transmitters, and valve positioners. DP-V2 isochronous mode is not supported.

Q4: What warranty and supply terms does NINERMAS offer for the SST-PFB-CLX?
NINERMAS provides a 12-month warranty on all SST-PFB-CLX units from the date of delivery. Each unit is pre-shipment tested under powered conditions with a documented test report. Long-term inventory reservation and buffer stock programs are available for customers with ongoing maintenance requirements. Contact sale@ninermas.com or +0086 187 5021 5667 for volume pricing and supply commitment terms.