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ET200SP AQ 4xU/I ST Module Derating & Operation at Higher Temperatures

Dear Robert,

Regarding your question about the AQ 4xU/I ST (6ES7135-6HD00-0BA1) module's behavior at temperatures exceeding 30°C, the module will not necessarily shut down. Instead, the available output current per channel is reduced due to derating. You will likely not get a hard error, but performance will be limited.

As detailed in the manual (see page 24), the permissible current depends on the ambient temperature and the load (actuator resistance). With a 200 Ohm load (Samson positioners), and temperatures between 20-35°C, you'll need to consult the derating graphs to determine how many channels can operate at their full specification.

For your application (200 Ohm load, 20-35°C ambient): You may be able to use all 4 channels at lower temperatures, but fewer channels as the temperature approaches 35°C. If you need to guarantee full performance of all 4 channels consistently, the AQ 2xU/I HF module might be necessary, despite the higher cost.

The CPU 315-2 PN/DP does not directly influence the module's derating characteristics; it's purely a function of the module and ambient temperature/load.

Sincerely,

Siemens Self Support

ET200SP Digital Output Leakage Voltage - Siemens Self Support

Hello,

The 5.8V leakage voltage on the ET200SP DO modules when off is a known phenomenon, particularly with inductive loads or long cable lengths. Here's a breakdown and potential solutions:

• Cause: The ET200SP DO modules utilize a "leaky" output stage design. This means a small current can flow even when the output is off, resulting in the observed voltage. This is more pronounced with loads like LEDs, which have low forward voltage requirements.
• Cable Length & Load: The 3-meter cable length with 0.75mm² wire, combined with LEDs, exacerbates the issue. Cable capacitance and LED impedance contribute to the voltage drop and visible illumination.
• CPU vs. ET200SP: The CPU outputs likely have different output stage characteristics, explaining why you don't see this behavior there.

Recommendations:

1. Series Resistors: Add a series resistor (e.g., 1kΩ to 2.2kΩ, calculate based on LED forward voltage and desired current limiting) in each output circuit, closer to the LED. This will reduce the leakage current and dim the LEDs when the output is off.
2. Suppression Diode: While LEDs offer some reverse protection, a small suppression diode (e.g., 1N4148) in parallel with each LED (cathode to positive) can help shunt any reverse leakage current.
3. Check Wiring: Ensure proper grounding and shielding of the cables to minimize noise and potential interference.
4. Firmware Update: Verify that the IM155-6 PN ST and the DO modules have the latest firmware versions installed via Siemens Industry Online Support.

If the problem persists after trying these suggestions, please open a support request with detailed information about your setup through SiePortal for further investigation.