Description
Application Scenarios
A European automotive tier-one supplier was commissioning a new body-shop cell built around a PROFIBUS-DP master PLC and a long chain of remote I/O, valve islands, weld controllers and drive units. The problem was sequencing: the PLC programme and the network configuration were finished, but the field devices were still being installed on the line. Every week of waiting cost the project money, and the integrator had no way to prove that the master’s I/O scan, diagnostic handling and fault recovery logic actually worked under a full network load.
The SST 5136-PBMS-ISA turned that dead time into productive engineering time. Installed in a standard ISA slot of the commissioning laptop’s docking station, the 5136-PBMS-ISA emulated up to 125 DP slave stations on a single physical PROFIBUS connection, presenting the master with a fully populated network long before a single real device was wired. Because the SST 5136-PBMS-ISA connects as a passive station during monitoring, it can also be clipped onto a live network without adding to the master’s scan time, so the same card later served as a packet-level data logger during start-up fault finding.
The pain point it addresses is the classic chicken-and-egg problem of fieldbus commissioning. Instead of paying for a full network of hardware to be installed early, or shipping untested logic to site, the team validated the master against a simulated load and arrived on site with a configuration that already worked. Beyond commissioning, the SST 5136-PBMS-ISA solves a second, longer-term problem: it gives PC-based HMI, SCADA and OI software a direct, deterministic PROFIBUS connection on machines whose host computers only have ISA slots, which removes any pressure to replace a working control platform just to gain fieldbus access.
Parameter
| Main Parameters | Value / Description |
|---|---|
| Product Model | 5136-PBMS-ISA (SST 5136 series, PROFIBUS multi-slave variant) |
| Manufacturer | SST / S-S Technologies, Woodhead Industries, now Molex |
| Product Category | PROFIBUS multi-slave network interface card, half-length 16-bit ISA |
| Supported Roles | DP master, DP slave, FMS client, FDL (layer 2) messaging, all simultaneously |
| Multi-Slave Capability | Emulates or monitors up to 125 DP slave stations on one PROFIBUS connection |
| Onboard Processor | Intel i960 embedded processor executing the PROFIBUS protocol stack |
| Onboard Memory | 512 KB local RAM, 512 KB shared 16-bit RAM paged to the host in 16 KB windows, 512 KB sectored flash for firmware and configuration |
| Host Resource Footprint | Occupies 16 KB of host memory and 8 I/O port addresses, base address 250h to 257h |
| Baud Rates | 9.6 K, 19.2 K, 93.75 K, 187.5 K, 500 K, 750 K, 1.5 M, 3 M, 6 M and 12 Mbaud |
| Network Connector | Standard PROFIBUS 9-pin D-sub (DB-9F) plus 5-pin Phoenix connector, no external bus connector required |
| Electrical Interface | RS-485 PROFIBUS physical layer with galvanic isolation; onboard termination selectable via Phoenix connector |
| Interrupt Support | Selectable interrupts 3, 5, 7, 9, 10, 11, 12 and 15 |
| Power Requirement | Maximum 450 mA at 5 VDC from the ISA slot, roughly 2.3 W |
| Environmental Limits | Operating 0 °C to 50 °C (32 °F to 122 °F); storage -25 °C to 70 °C; 5% to 95% humidity non-condensing |
| Diagnostics | Diagnostic LED indicating network error, DP master, DP slave, FMS client and FDL status; per-slave diagnostic, parameterization and I/O data viewable via SST PICS software |
| Compliance and Format | CE and FCC Class A; half-length ISA card, approximately 0.14 kg, roughly 176 mm x 128 mm x 22 mm |
Technical Principles and Innovative Values
Innovation Point 1: Protocol offload onto a dedicated i960 co-processor. The SST 5136-PBMS-ISA does not ask the host PC to run the PROFIBUS stack. An onboard Intel i960 processor with 512 KB of local RAM executes token management, cyclic polling, slave emulation and diagnostic handling entirely on the card. The practical result is deterministic fieldbus timing that is immune to Windows scheduling jitter, multitasking load or the host application’s response time. On 1990s and early-2000s hardware, where the host CPU was often the bottleneck, this architecture is the reason the 5136-PBMS-ISA could hold a fully loaded 12 Mbaud network without dropping a cycle.
Innovation Point 2: Paged dual-port memory that breaks the 244-byte barrier. Conventional PROFIBUS slave interfaces are limited to 244 bytes in and 244 bytes out per slave. The SST 5136-PBMS-ISA provides 512 KB of shared 16-bit RAM that the host maps through a 16 KB window by writing to a page register, which removes that limitation entirely. All tables, buffers, diagnostic data and parameterization records live in this shared block, so the host application reads and writes process data through a simple memory interface rather than through slow, message-based driver calls.
Innovation Point 3: One card, four simultaneous personalities. The 5136-PBMS-ISA can act as a DP slave, a DP master, an FMS client and an FDL layer-2 message endpoint at the same time, and multiple DP Class 1 masters can communicate to a single multi-slave card. This is what allows the same hardware to serve as a commissioning simulator in the morning and a production HMI interface in the afternoon, and it is a capability that no single-role master card can match.
Innovation Point 4: Non-intrusive network monitoring. When the SST 5136-PBMS-ISA is configured as a passive station, it captures traffic without participating in the token rotation, so it does not extend the DP master’s I/O scan time or perturb the network it is measuring. For active stations this is a real constraint, and it is precisely why the 5136-PBMS-ISA is trusted for diagnosing intermittent faults on networks that cannot be stopped.
Innovation Point 5: Flash-stored configuration and firmware for autonomous restart. The 512 KB of sectored flash holds both the firmware module and the PROFIBUS network parameters, including the slave configuration. After a power cycle the SST 5136-PBMS-ISA reloads its own configuration from flash without any host intervention, so a control room PC that reboots overnight comes back onto the network automatically instead of waiting for an engineer to download a configuration file.
