6ES7405-0DA02-0AA0 is a power module (PS 405) from Siemens SIMATIC S7-400 series, which can convert 24/48/60V DC input voltage into 5V DC and 24V DC power required by the system. It has a maximum output current of 4A (5V DC) and 0.5A (24V DC), with a typical power loss of about 16W and a typical effective power reception of about 48W4. The module is designed for industrial automation environments, with a power outage/power-off crossover time (20ms) of 4, and supports optional buffer batteries (AA type lithium batteries, 3.6V/2.3Ah) to maintain system operation in the event of short-term power outages.

If installing EXPANDER MODULE POWER SUPERY SIMATIC S7-400 on PURIFIER EXPANDER: 6ES7405-0DA02-0AA0，we should do as below:

Safe power outage: It is necessary to cut off the power supply to the PURIFIER EXPANDER system and all related equipment.

1. Module installation:

Carefully insert the 6ES7405-0DA02-0AA0 module into the designated power slot of the rack along the guide rail, ensuring that its back connector is firmly in contact with the backplane bus.

2. Power connection:

Use 3x1.5 mm ² wire (full wire or twisted wire with core wire end sleeve, outer diameter 3mm to 9mm) 

Connect the DC power cord correctly to the input terminals (L+, M) of the module according to the label or manual instructions, paying attention to polarity.

3. Power on test:

Do not connect the main system power supply first, and check separately whether the input voltage of the power supply is within the allowable range and the polarity is correct.

Connect the power and observe if the status indicator light on the module (if any) is displaying normally.Use a multimeter to measure whether the 5V and 24V outputs of the backplane bus are normal and stable.

4. System startup and diagnosis:

After confirming that the power output is normal, power on the entire system.

Access the hardware diagnostic function through PLC programming software (such as STEP 7) to check if all modules are correctly identified and there are no fault alarms.

How to make PURIFIER EXPANDER more comprehensive in terms of functionality,

Consider pairing with digital input/output modules: used to connect switches, buttons, sensors (inputs), as well as indicator lights, relays, valves (outputs).

If paired with 6ES7421-1BL01-0AA0 (32-bit digital input module). These types of modules usually have LED status indicators for easy diagnosis.

Alternatively, it can be paired with a communication expansion module: used to expand the system's communication interface, connect distributed I/O, HMI, upper computer or other vendor devices, and enhance system integration capabilities.

Such as pairing: EXM448-2 communication expansion module (supporting various mainstream industrial communication protocols such as PROFIBUS-DP, PROFINET IO, Ethernet/IP, etc.)

I believe that using your PURIFIER EXPANDER will be more efficient.