Description
Application Scenarios
At a regional wastewater treatment plant in Western Europe, the original S200 control system had been running continuously for more than 22 years. During a capacity expansion of the aeration basins, operators noticed that several ageing digital output modules were switching sluggishly—contactor commands arrived late, and the resulting mistiming between blower starters caused periodic 500 A inrush spikes that occasionally tripped the main LV switchboard.
The maintenance team sourced original surplus Schiele 2_423_451_00 modules as direct replacements. Because the 2_423_451_00 slots straight into the existing S200 rack backplane without re-engineering, re-wiring or software reconfiguration, the swap was completed during a single weekend maintenance window. The new modules’ typical <1 ms on/off switching delay restored crisp, deterministic sequencing, while the built-in group isolation (3 kV AC between outputs and bus) eliminated the cross-talk that had previously caused erratic contactor pickup. Six months after the retrofit, the plant recorded zero switchboard trips attributable to output timing.
Parameter
| Main Parameters | Value/Description |
|---|---|
| Product Model | 2.423.451.00 (also written 2_423_451_00 / 2 423 451 00) |
| Manufacturer | Entrelec Schiele GmbH |
| Product Category | PMO Transistor Digital Output Module |
| Compatible System | Schiele Systron PM S200 / PM S250 DCS-PLC |
| Output Channels | 8 transistor outputs, grouped and electrically isolated (8 points = 1 group) |
| Rated Output Voltage | 20–30 V DC (nominal 24 V DC) |
| Current per Channel | 1 A continuous |
| Total Module Current | ≤ 4 A |
| Switching Delay | < 1 ms typical (on and off) |
| Isolation Voltage | 3 kV AC between output and bus/power supply |
| Output Protection | Short-circuit current limiting, overload detection, reverse polarity protection |
| Sensor Power Supply | 20–30 V DC, 100 mA, short-circuit protected |
| Bus Power Consumption | ≤ 155 mA @ 26.5–31.6 V DC |
| Bus Fault Behaviour | Holds last output state for up to 1 second after bus failure |
| Status Indicators | Green LEDs for power supply normal + per-channel output status |
| Mounting Method | 35 mm standard DIN rail |
| Cooling | Natural convection |
| Operating Temperature | -20 °C to +60 °C |
| Storage Temperature | -40 °C to +85 °C |
| Relative Humidity | 5%–95% RH, non-condensing |
| Vibration Resistance | 5–150 Hz, 0.5 g |
| Shock Resistance | 10 g (11 ms half-sine) |
| Protection Rating | IP20 (cabinet installation) |
| Certifications | VDE, CE |
| Weight | Approx. 0.2 kg |
| Lifecycle Status | Discontinued by OEM — available as original spare / refurbished / surplus |
Technical Principles and Innovative Values
Innovation Point 1 — Grouped electrical isolation with a 3 kV AC barrier. The Schiele 2_423_451_00 isolates all eight outputs as a single galvanically separated group from the system backplane and bus logic. This 3 kV AC barrier prevents voltage transients on one field device from propagating back into the controller, protecting the entire S200/S250 rack.
Innovation Point 2 — Intelligent fault containment. When a channel experiences a short circuit or overload, the 2_423_451_00 rapidly current-limits and reports the fault via LED and system diagnostics—without sustaining damage or disrupting the other healthy channels in the group. This “fault containment” philosophy keeps the rest of the process running even during a field-wiring incident.
Innovation Point 3 — Sub-millisecond switching for precise sequencing. With a typical <1 ms on/off delay, the Schiele 2_423_451_00 delivers the rapid response required for precise actuator sequencing and safety-related shutdowns. In staged motor starting or interlocked valve manifolds, this speed directly translates into reduced mechanical stress and tighter process control.
Innovation Point 4 — Bus power-fail memory. The module retains the last valid output state for up to one second after a bus failure, giving higher-level controllers and operators a short grace period to react before field devices see an undefined state—an important advantage in continuous-process applications.
Innovation Point 5 — Diagnostic visibility at the cabinet door. Green power and per-channel LEDs make output activity immediately visible without a laptop or multimeter, shortening fault-finding on the shop floor.
