If you build machines that must move fast, stop safely, and explain themselves when something goes wrong, the Siemens 6ES7136-6DB00-0CA0 is the kind of I/O you want sitting close to the actuators. This module is a SIMATIC ET 200SP fail-safe digital output (F-DQ) electronics module designed for distributed safety architectures, where safety logic runs in an F-CPU and the field I/O executes certified shutdown behavior through PROFIsafe.
The product type designation is F-DQ 4x24VDC/2A PM HF, delivered in the compact 15 mm ET 200SP form factor, and intended for safety-related switching of 24 V DC loads. Its design goal is simple: provide predictable switching, diagnostic transparency, and functional safety performance up to PL e / SIL 3 when used as intended in a properly engineered safety function.
Where it fits in a real machine
In practical terms, the 6ES7136-6DB00-0CA0 is typically used to drive safety-relevant actuators such as solenoid valves, contactor coils (often via suitable interfacing), safety-rated pneumatic valves, or other 24 V DC devices that must be switched off reliably during an E-stop, guard door open, or protective stop. Because it is an ET 200SP module, it supports a neat distributed layout: mount it near the machine section it controls, keep wiring short, and bring safety communication over the network/backplane rather than dragging every signal back to a central cabinet.
It is also engineered for modern Siemens toolchains: the data sheet notes configuration via STEP 7 (TIA Portal) from V12, and PROFINET integration via GSD (listed as V2.31 in the data sheet).
Key Technical Specifications (At a Glance)
| Item | Specification |
|---|---|
| Order number | 6ES7136-6DB00-0CA0 |
| Module type | ET 200SP fail-safe digital output (F-DQ) |
| Outputs | 4 transistor outputs |
| Rated supply | 24 V DC (permissible range 19.2 to 28.8 V DC) |
| Output current | 2 A per channel (signal “1” rated), residual current max. 0.5 mA (signal “0”) |
| Total output current | Max. 6 A per module; 2 A max per channel (derating may apply) |
| Switching capacity | Resistive max. 2 A; lamp load max. 10 W |
| Switching frequency | Resistive max. 30 Hz; lamp load max. 10 Hz; inductive max. 0.1 Hz (DC-13 reference) |
| Cable length | Shielded max. 1000 m; unshielded max. 500 m |
| Ambient temperature | Horizontal 0 to 60 °C; vertical 0 to 50 °C |
| Dimensions (W×H×D) | 15 mm × 73 mm × 58 mm |
| Weight | 65g |
| Functional safety | Suitable for safety functions; up to PL e and SIL 3 (per data sheet) |
Protection, Diagnostics, and “Machine Reality” Behavior
A safety output module isn’t judged only by how it behaves on a good day. It’s judged by how it behaves when the wiring is ugly, the load is weird, or someone pinched a cable in a door.
The 6ES7136-6DB00-0CA0 includes built-in protective and diagnostic features including:
| Diagnostic / protection feature | What it does (why you care) | Data sheet detail |
|---|---|---|
| Short-circuit protection | Helps prevent damage and triggers diagnostics when an output is shorted | Typical response threshold > 3.3 A |
| Overload protection | Detects sustained overload beyond normal operating current | Typical response threshold 2.9 A |
| Open-circuit (wire break) detection | Detects missing load/current path (depending on wiring and conditions) | Typical response threshold 8 mA |
| Diagnostic alarms / interrupts | Lets the controller react immediately rather than polling | Diagnostics function and diagnostic alarm supported |
| Status indication LEDs | Helpful for commissioning and troubleshooting, but not a safety signal | Manual warns LEDs are not safety-rated indicators |
The equipment manual also describes diagnostic interrupt behavior and example faults (such as internal error, time monitoring, internal supply failure, output short to L+ or ground, wire break), which is exactly what you want when commissioning: the difference between “it doesn’t work” and “it doesn’t work because channel X is shorted to ground.”
Functional Safety Notes That Actually Matter
1) Safety performance and the “dark test” tradeoff
Siemens documentation highlights that you can disable the dark test to prevent unwanted actuator reactions (for example, brief de-energizing of a magnetic drive). But disabling the dark test reduces the maximum achievable safety rating to SIL2 / Cat.3 / PLd.
It also adds an important operational requirement: for SIL2/Cat.3/PLd with disabled dark test, there must be a 1 → 0 signal change at least once per year, with the “0” lasting at least 2 seconds (simply power-cycling the module is not sufficient).
Finally, Siemens warns that with “Disable dark test,” cross-circuits between channels that are both at “1” may not be detected, and if a short/cross-circuit is detected when executing the shutdown, the module may passivate and shut down outputs together—meaning your safety design must account for the required error detection time in your applicable standards.
2) Recommended wiring for robust safety outcomes
The older but still useful equipment manual discusses wiring guidance intended to protect against cross-circuits between switching elements in fail-safe outputs, and notes that following the recommended scheme can achieve SIL3 / Cat.4 / PL e.
Response Time Basics (What your safety calculations will touch)
For safety, “fast enough” is not a vibe; it’s a calculated number. Siemens provides a response-time definition and formula framework for F-DQ modules. The response time is defined as the interval between the incoming safety message frame from the backplane bus and the resulting output signal change. The documentation lists a maximum cycle time of 15.5 ms, and shows that maximum response time depends on cycle time plus configured dark test / switch-on timing (and, in some cases, test time).
| Response-time element | What Siemens provides |
|---|---|
| Maximum cycle time | 15.5 ms |
| General max response time structure | Based on multiples of cycle time plus the larger of configured dark test time and switch-on time |
Engineering and Integration Checklist
| Topic | Practical recommendation | Source basis |
|---|---|---|
| BaseUnit compatibility | Verify BaseUnit type (data sheet notes BU type A0) before ordering spares | |
| Load type | Respect switching limits (resistive vs inductive vs lamp) and derating where applicable | |
| Cable length and EMC | Use shielded cabling where needed; note max lengths and routing practices | |
| Diagnostics strategy | Use diagnostic interrupts and controller-side logging to shorten troubleshooting time | |
| Safety configuration | Decide early whether dark test must be disabled; it affects achievable SIL/PL and maintenance requirements |
Summary
The Siemens 6ES7136-6DB00-0CA0 is a compact, safety-rated ET 200SP output module built for 4-channel 24 V DC fail-safe switching at up to 2 A per channel, with protections and diagnostics suited to real industrial wiring conditions. Its documented safety capability reaches PL e / SIL 3 under appropriate design conditions, and Siemens provides practical engineering guidance for wiring, diagnostics, and response-time calculation—exactly what a safety engineer needs to turn “parts” into a validated safety function.
