Power Module 6ES7138-4CA01-0AA0 6ES7 138-4CA01-0AA0 6ES7138-4CAO1-OAAO

Siemens 6ES7138-4CA01-0AA0 | SIMATIC DP PM-E Power Module for ET 200S — 24V DC / 10A / Diagnostics / 15mm

PM-E — Power Entry Point for the ET 200S Module Group

In a SIMATIC ET 200S distributed I/O node, the PM-E (Power Module — Electronic) defines the power supply domain for the modules that follow it to the right on the terminal row. Each PM-E receives 24V DC from an external supply and distributes it to the electronic supply rail of adjacent I/O modules. Modules to the right of a PM-E draw their operating power from that PM-E's supply group until the next PM-E or terminal row boundary.

The 6ES7138-4CA01-0AA0 provides potential separation — electrical isolation between the load voltage (the 24V DC from the external supply) and the PROFIBUS DP backplane bus. This separation keeps field supply disturbances from reaching the backplane communication bus, and isolates supply groups from each other when multiple PM-E modules are used in one ET 200S node.

Diagnostics for missing load voltage are built in. If the 24V DC supply to the PM-E fails or drops out of specification, the module sends a diagnostic message to the PROFIBUS DP master — the controller receives the fault notification automatically without requiring external monitoring wiring.

Key Specifications

External Short-Circuit Protection — Required Design Step

The 6ES7138-4CA01-0AA0 has no internal short-circuit protection on the load voltage side. An external protective device must be installed upstream — a circuit breaker with tripping characteristic C is specified. This is a design requirement, not an option. Without the external breaker, a short circuit in the field wiring or a connected module has no current-limiting protection from the PM-E itself. Size the external breaker for the connected load, not just the 10A module maximum.

FAQ

Q1: What does "PM-E" mean in the ET 200S naming convention?

PM-E stands for Power Module Electronic. It is the module that provides the electronic supply voltage to a group of adjacent ET 200S I/O modules. Unlike the PM-D (Power Module Discrete), which supplies current to discrete output loads, the PM-E powers the electronic circuits of the I/O modules themselves. Multiple PM-E modules in one node segment the electronic supply into independently powered groups.

Q2: Why is an external circuit breaker with characteristic C required?

The 6ES7138-4CA01-0AA0 provides no internal short-circuit protection. Without an upstream breaker, a short circuit in the field wiring or a shorted module can draw unlimited current from the supply, damaging the PM-E and connected modules. Tripping characteristic C is specified because the PM-E and I/O modules present capacitive inrush current at power-on — the C curve's higher inrush tolerance prevents nuisance tripping during normal start-up while still protecting against true fault currents.

Q3: What does the missing load voltage diagnostic do in practice?

If the 24V DC input to the PM-E falls below the detection threshold, the module generates a diagnostic message that the PROFIBUS DP master reads as a module fault. The master's PLC programme receives the fault, allowing the control system to react to the loss of ET 200S supply voltage — shutting down affected I/O gracefully or generating an alarm. This is significantly more informative than simply losing I/O function without explanation.

Q4: How many I/O modules does one 6ES7138-4CA01-0AA0 supply?

The PM-E supplies all ET 200S I/O modules in its power supply group — from the PM-E's position to the next PM-E or the end of the terminal row, whichever comes first. The number of modules depends on the current draw of each module in the group. Total current for all modules in the group must not exceed 10A at 60°C. Calculate the total electronic current draw of all modules in the group and verify it stays within this limit.

Q5: The 6ES7138-4CA01-0AA0 is discontinued. What is the current Siemens replacement?

The ET 200S system itself has been superseded by the ET 200SP platform. For existing ET 200S installations requiring PM-E module replacement, check Siemens' current parts availability through the Siemens Industry Mall. For new installations, the ET 200SP with its own power module variants is the current platform. Confirm current availability and any discontinued status with Siemens' own supply chain before specifying.