Description
Product Introduction & Engineering Value
When a ControlLogix system must talk to a large installed base of PROFIBUS DP devices, a native scanner that sits in the 1756 chassis is still the cleanest solution. The SST-PB3-CLX-RLL is that module. It functions as a PROFIBUS DP Master (and optionally Slave) and exchanges data with up to 125 remote slaves at speeds up to 12 Mbps.
The module occupies a single slot, draws power from the ControlLogix backplane, and presents a standard 9-pin D-Sub PROFIBUS connector. It supports both DP-V0 cyclic I/O and DP-V1 acyclic messaging, includes an Add-On Profile for Studio 5000 / RSLogix 5000, and can run Master and Slave functions simultaneously. Configuration and diagnostics are handled through the SST Console or the Rockwell AOP.
Technical Specifications
Module Type: Single-slot ControlLogix PROFIBUS scanner
Protocol Support: PROFIBUS DP-V0 Master/Slave, DP-V1 Master (Class 1 & 2)
Maximum Slaves: 125 I/O per Slave: Up to 122 words input and 122 words output
Total I/O Capacity: Approx. 1984 bytes input / 1968 bytes output (across 4 pages)
Baud Rates: 9.6 kbps to 12 Mbps (all standard PROFIBUS rates)
Network Connector: 9-pin D-Sub female (PROFIBUS)
Backplane Current: 850 mA @ 5 VDC; 1.75 mA @ 24 VDC
Operating Temperature: 0 to 60 °C
Diagnostics: 4-character display + COMM / SYS / OK LEDs
Configuration: RSLogix 5000 / Studio 5000 AOP + SST Console
Maximum Modules per Chassis: 8
Field Application & The “Trench” Experience
A Midwest process plant still ran a large PROFIBUS DP segment with valve positioners and remote I/O drops. The original scanner failed during a planned outage. The maintenance team installed an SST-PB3-CLX-RLL in an available 1756 slot, imported the existing configuration via the SST Console, downloaded the AOP, and brought the entire DP network back online without rewriting any ladder or migrating devices. The module’s ability to act as both Master and Slave simplified a temporary gateway requirement during the cutover.
Niche placements that fit this exact model:
- ControlLogix chassis that must scan a legacy PROFIBUS DP valve or drive network.
- Hybrid system requiring simultaneous Master and Slave operation on the same DP segment.
- Temporary or permanent bridge between a ControlLogix controller and an existing PROFIBUS installation that cannot be converted to EtherNet/IP.
SST-PB3-CLX-RLL
Transparency SOP: QA & Testing
- Visual inspection of the circuit board, connectors, and faceplate for damage or corrosion.
- Backplane power-up in a 1756 chassis; verify current draw and module recognition.
- PROFIBUS port continuity and isolation check.
- Firmware version confirmation and communication with SST Console.
- Master-mode scan of a known DP slave; verify cyclic I/O data exchange and diagnostics.
- Slave-mode operation test if applicable.
- Final functional burn-in followed by anti-static packaging.
The Veteran’s Tech Trap Guide
⚠️ Firmware and ControlLogix compatibility – This module was never fully validated on ControlLogix firmware revisions 24 and higher. Confirm controller firmware level before installation; newer controllers may require alternative solutions.
⚠️ Configuration memory – The module stores its PROFIBUS configuration in onboard flash. Always back up the configuration file before replacing the unit; a blank module will not automatically inherit the previous scan list.
PRO TIP: Use the 4-character display and LED status during commissioning. “OK” solid and “COMM” activity are the quickest indicators that the module has joined the backplane and is exchanging data on the PROFIBUS network.
Dynamic FAQ
Q: Is the SST-PB3-CLX-RLL still available new? A: The module is discontinued by Molex. Functional New Surplus and refurbished units are the practical source for direct replacements.
Q: Can this module operate as both PROFIBUS Master and Slave at the same time? A: Yes. It supports simultaneous Master and Slave operation on the same network.
Q: What is the maximum number of slaves it can scan? A: Up to 125 PROFIBUS DP slaves.
Q: Does it require a separate power supply? A: No. It draws all power from the ControlLogix backplane (primarily 5 VDC).
Q: What warranty and authenticity documentation come with New Surplus or Refurbished stock? A: Units ship with functional test records, clear origin marking (New Surplus or Refurbished), firmware version verification, and a standard parts-and-workmanship warranty.
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