BX-DM1E-10ED23D: Sizing Solar Power Without CPU Slowdown

Brian Holt3 min read
Application NoteAutomationDirectPLC Hardware
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A field report confirms that a BX-DM1E-10ED23D with no expansion modules has operated from a small 12 V battery in a solar-powered tank-level application. The evidence does not establish that processor speed can be reduced, that doing so lowers current, or that the reported installation is correctly sized. Size the power system from measured energy consumption and the required cloudy-weather autonomy instead.

What the Field Report Establishes

The controller supported a serial-data-radio tank-level installation without reported special power-saving measures. The system reportedly became problematic after five cloudy days. The operator estimated that the existing panel might be 60 W but did not know the inherited panel or battery specifications, so those values cannot serve as a verified design recommendation.

Item Evidence status Engineering use
Controller BX-DM1E-10ED23D Confirmed application device
Battery Small 12 V battery; capacity unknown Voltage is known, stored energy is not
Solar panel Possibly 60 W Unverified estimate; do not use as a sizing basis
Expansion modules None Reported configuration boundary
Load function Tank-level reporting by serial data radio Radio and sensor loads must be included
Observed limitation Problem after five cloudy days Indicates inadequate autonomy, recharge margin, or battery condition under that event

Do Not Assume CPU Slowdown Reduces Current

No supplied evidence identifies a processor-speed control or quantifies a current reduction from slowing the processor. Treat CPU slowdown as unsupported until product documentation or a controlled input-current test demonstrates both that the setting exists and that it produces a useful reduction without impairing control or communications.

The field installation ran without special controller changes. This supports evaluating the complete power budget before pursuing an unverified controller modification.

Size the Solar and Battery System

Measure the complete enclosure load at 12 V over representative operation, including the controller, level sensor, serial radio, and any conversion or regulation losses. A momentary current reading is insufficient when radio transmission or sensor operation changes the load.

  1. Record battery voltage and current over a representative operating cycle, including radio transmissions.
  2. Integrate the measured power over time to obtain daily load energy. Use E_load = ∫ V(t) × I(t) dt.
  3. Select the required no-sun autonomy and size usable battery energy from E_battery,usable ≥ E_load,daily × autonomy_days. Do not substitute the reported five-day cloudy event for the project requirement without reviewing site risk.
  4. Size the panel and charging system to supply the daily load and restore depleted battery energy under the site's available solar conditions.
  5. Verify operation through the required cloudy interval while monitoring battery voltage, controller operation, sensor readings, and serial communications.

Verification and Failure Isolation

If the system fails during extended cloud cover, distinguish insufficient solar input from loss of battery capacity and excessive load. Log panel charging, battery voltage, and load current across the event. A successful design maintains the required controller and radio functions through the specified autonomy interval and subsequently recharges the battery under the design solar conditions.

FAQ

Can I slow the BX-DM1E-10ED23D processor to reduce current?

The evidence does not identify a processor-speed setting or demonstrate any current reduction. Confirm the capability in product documentation or by controlled measurement before using it in the power budget.

Will a 60 W solar panel power a BX-DM1E-10ED23D?

The reported panel was only estimated to be 60 W, and its installation had problems after five cloudy days. Determine suitability from measured daily energy use, charging losses, local solar availability, and required autonomy.

How large should the 12 V battery be for a BRX solar application?

Measure the complete system's daily energy and calculate E_battery,usable ≥ E_load,daily × autonomy_days. The evidence gives no battery capacity, so it cannot support a specific battery size.

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