Technical Specifications

Main Features and Advantages

Integrated 24 V DC PSU eliminates a rack slot.​ The defining trait of the **6ES5100-8MA01 versus the -8MR01 (which expects a separate PS 930 PSU module in the rack) is the onboard regulator: 24 V DC in from the cabinet’s SITOP or bulk 24 V rail, internally stepped to +9 V and +5.2 V for CPU logic and backplane distribution. This means the S5-100U rack can be built as “CPU + I/O modules only” without sacrificing a slot to a PS 930—valuable when the I/O count pushes the six-module digital limit and every slot counts. For skids already fed from a central 24 V DC distribution (common in process packages and OEM machines), the 6ES5100-8MA01​ drops in cleanly.Six digital + two analog local-module capacity.​ The 6ES5100-8MA01​ controls the S5-100U backplane to address six 8-channel digital modules (DI 24 V DC, DO relay, DO transistor, etc.) and two 4-channel analog modules (AI ±10 V / 0–20 mA / TC / RTD, AO ±10 V / 0–20 mA) on the local tier. That’s a configurable mix—e.g., four DI + two DO + two AI, or any permutation—giving far more flexibility than the fixed 10 DI/6 DO of the S5-90U. For applications where even more I/O is needed, the 6ES5100-8MA01​ backplane hands off to an IM 316 (6ES5316-8MA12) for multi-tier expansion, pushing the practical ceiling well beyond the local 256-DI/DO envelope.1.5–3 µs bit execution in a sub-k memory footprint.​ The 6ES5100-8MA01​ delivers deterministic S5 scan performance that, while eclipsed by modern S7-1200/1500, remains entirely adequate for sequence logic, interlock chains, motor permissive strings, and light loops executed in FB41-equivalent S5 blocks. At ~15 ms scan for 1K logic steps, the 6ES5100-8MA01​ handles packaging-station sequencers, conveyor-zone logic, and skid auxiliaries without breaking stride. The 1024-statement RAM (~4 KB) is small by today’s standards but was sized for the S5-100U target: a mid-size ladder with a few analog FB calls fits comfortably; larger programs push toward the CPU 102 (2048 statements) instead.Battery-backed RAM + EPROM submodule path.​ Like the S5-90U, the 6ES5100-8MA01​ stores the STEP 5 program in battery-backed RAM (3.6 V lithium, ~2 year hold). For production machines subject to power cycling, burning the validated program to an S5-375 EPROM submodule (plugged into the CPU front socket) eliminates battery-dependency—a standard deployment pattern on S5-100U cells that run 24/7 but face occasional mains drops. The 6ES5100-8MA01​ front also carries the TTY (20 mA current-loop) PG port for program load/download; modern PCs need a TTY-to-USB or TTY-to-RS-232 adapter plus STEP 5 running in a DOS box or VM, since Siemens never ported S5 to Windows natively beyond STEP 5 v7.Entry point in the S5-100U three-tier.​ The 6ES5100-8MA01​ (CPU 100) sits below the CPU 102 (2 KB RAM? wait table ambiguous, but CPU 102 adds communication capability and more memory, CPU 103 adds Profibus DP and integral RTC). Choosing the 6ES5100-8MA01​ over 102/103 made sense when the application had zero need for onboard comms—no HMI link, no Profibus, just standalone sequence control. That profile—”smart-enough processor, no comms, integrated 24 V PSU”—matches a surprising number of still-running S5-100U machines: packaging-head controllers, conveyor-zone sequencers, building-HVAC plant-room aux, small-press safeties.

Application Field

The 6ES5100-8MA01​ is encountered wherever an S5-100U rack was originally specified as the machine or skid controller—typically where the S5-90U I/O count (10 DI/6 DO max) was insufficient but the S5-115U rack (full-size, 19-inch) was over-engineered and too costly. In packaging-OEM lines, the 6ES5100-8MA01​ commonly anchors a mid-size station: a cartoner flight-bar section with 3–4 DI modules (photoeyes, prox, guard-door) and 1–2 DO modules (solenoid valves, beacon, interposing relay for 230 V contactor), plus perhaps one AI module for a sealing-bar thermocouple—total 30–60 I/O, well within the six-digital + two-analog local budget. In conveyor-zone panels for distribution-center sortation, the 6ES5100-8MA01​ runs diverter-arm logic and slug-photo strings, with IM 316 expansion if the zone grows beyond one tier.Process-skid applications form a second cluster: CIP-return skids, heat-exchanger package controls, compressor-lube-panel monitors, and small water-treatment package plants where the EPC specified S5-100U for cost. The integrated 24 V PSU on the 6ES5100-8MA01​ aligns with these skids’ typical 24 V DC panel rail (from a SITOP feeding the whole skid). Building-services and HVAC plant rooms—chiller aux, cooling-tower cell, AHU freeze-stat strings—round out the list: the 6ES5100-8MA01​ handles lead-lag pump logic, float-switch DI, contactor DO, and maybe one AI for a temperature transmitter, all on local modules without IM expansion. Across all these, the shared profile is “machine/skid commissioned ~1992–2008, S5-100U CPU 100 original, still running, 6ES5100-8MA01​ now 15–25 years old.” The module is not greenfield—Siemens steers new designs to S7-1200—but as a lifecycle-extending spare it keeps assets online while the S7 migration business case is built.