Description
Schneider Modicon AS-BADU-204 | 4-Channel Analog Input | TSX Compact PLC
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Schneider Electric / Modicon |
| Model | AS-BADU-204 |
| Product family | TSX Compact |
| Module type | Analog input |
| Number of channels | 4 |
| Input signal | ±500 mV |
| Temperature input | Pt100 RTD |
| Resolution | 11 bits + sign |
| Electrical isolation | No isolation |
| Input impedance | Greater than 10 MΩ for voltage measurement |
| Voltage overload | ±24 VDC |
| Pt100 range | -200 to +800°C |
| Pt100 resolution | Approximately 0.25°C |
| Conformal coating | No |
| Approx. weight | 0.3 kg |
| Installation | TSX Compact PLC rack |
| Manufacturer status | Discontinued |
Schneider’s Compact Automation Platform documentation identifies AS-BADU-204 as the analog input module for ±0.5 VDC linear measurement and Pt100 RTD, with 11 bits plus sign. The same documentation specifies four inputs and no electrical isolation.
Schneider’s M340 migration documentation independently identifies the AS-BADU-204 as a 4-channel ±0.5 V / Pt100 analog input module.
Product Introduction
The Schneider Modicon AS-BADU-204 is a legacy TSX Compact analog input module designed primarily for low-level voltage and temperature measurement. It provides four input channels supporting ±500 mV signals and Pt100 RTDs, making it suitable for temperature and other low-level process measurements within older Modicon PLC installations.
Unlike newer isolated analog modules, the AS-BADU-204 is documented as non-isolated. That distinction matters when connecting field instrumentation with different ground potentials or when migrating an old Compact installation to a newer PLC platform. Schneider’s migration documentation notes that the M340 equivalent offers channel-to-channel and channel-to-bus isolation that the original AS- does not.
AS-BADU-204
Application Scenarios & Field Pitfalls — Engineer’s Perspective
Engineering Pain Point
The AS- is easy to misidentify because some reseller databases simply describe it as a generic “analog input” module. Its actual signal range is much narrower: the documented configuration is intended for Pt100 and ±500 mV measurement, not conventional 0–10 V or 4–20 mA process inputs.
Typical Applications
- Pt100 temperature measurement — monitoring process, equipment, bearing, or machine temperatures.
- Low-level analog measurement — acquiring bipolar signals within the ±500 mV range.
- TSX Compact PLC systems — maintaining legacy Modicon control cabinets.
- Legacy machine automation — temperature and instrumentation acquisition where the original Compact architecture remains in service.
Technical Pitfalls to Avoid
- Do not substitute AS-BADU-205 without checking the signal type. AS-BADU-205 is a different analog module intended for voltage/current measurement, while AS- specifically supports ±500 mV and Pt100. Schneider’s compatibility table distinguishes these modules clearly.
- Do not assume 4–20 mA capability. The documented AS- specification is centered on ±500 mV and Pt100. A current-loop transmitter normally requires a different Compact analog input module.
- Account for the lack of isolation. The original module does not provide channel-to-channel or channel-to-bus isolation. This becomes particularly important when replacing it with a modern module during a migration project.
- Check the RTD wiring configuration. Pt100 installation wiring and lead resistance affect temperature accuracy. Confirm the actual sensor wiring arrangement and the existing PLC program’s scaling before replacing the module.
- Do not use the newer M340 equivalent as a blind drop-in replacement. Schneider identifies BMX ART 0414 as a migration counterpart, but also notes functional differences, including isolation and the lack of the original ±0.5 V range.
Related Products
- Modicon AS-BADU-205 — 4-channel analog input module for voltage/current signals; different signal range from the AS-.
- Modicon AS-BADU-206 — isolated 4-channel analog input with additional voltage/current ranges.
- Modicon AS-BADU-211 — higher-density analog input module supporting thermocouple, RTD, voltage and current measurements.
- Modicon AS-BADU-214 — broader-range 8-channel analog input module with voltage, current and RTD capabilities.
- Modicon AS-BADU-212 — 8-channel universal analog input module with thermocouple, RTD, voltage and current capability.
- Modicon AS-BADU-254 — related Compact analog input hardware.
- Modicon AS-BADU-256 — later Compact analog input configuration.
- Modicon BMX ART 0414 — M340 4-channel isolated TC/RTD module identified by Schneider as a migration counterpart, but not a direct electrical equivalent in every respect.
Procurement Note
For , the critical identification is:
Schneider Electric / Modicon AS- — TSX Compact 4-channel analog input module — ±500 mV / Pt100 — 11-bit + sign — non-isolated.
Do not purchase based solely on the generic description “analog input module.” Verify the four-channel configuration, Pt100 requirement, ±500 mV signal range, TSX Compact rack compatibility, and non-isolated architecture.
For a migration to Modicon M340, Schneider explicitly identifies BMX ART 0414 as a compatible migration option, but also documents functional differences. The original AS- should therefore be retained when exact legacy signal behavior is required.
