# CIP Safety

Protocols · `CIP Safety` · verification: source checked

CIP Safety is a functional safety communication protocol that extends the Common Industrial Protocol (CIP). It lets safety controllers, safety I/O blocks, interlock switches, light curtains, drives, and other safety devices communicate with standard devices on the same industrial network. It is certified by TÜV Rheinland as a black channel protocol and supports applications up to SIL 3 according to IEC 61508.

## Specification

| Property | Value |
|---|---|
| Transports | ethernet_l2, other |
| Architecture | producer consumer |
| Encoding | binary |

## Connected

- Related: [EtherNet/IP](https://machineschema.com/protocol/ethernet-ip.md), [IEC 61508-1:2010](https://machineschema.com/standard/iec-61508.md)

## Safety

- CIP Safety is certified by TÜV Rheinland as a black channel protocol; safety integrity is not dependent on the physical media.
- CIP Safety supports SIL 2 for moderate-risk applications and SIL 3 for critical applications according to IEC 61508.
- CIP Safety supports products based on ISO 13849 PLd-Cat3 (~SIL2).
- CIP Safety mechanisms detect errors and place devices into a safe state when necessary.
- Configuration ownership can be enforced to ensure safety configurations cannot be changed by other devices on the network.
- The protocol is present only in safety controllers and field devices, which prevents standard devices from posing as safety devices.

## Study notes

- CIP Safety extends CIP by adding safety application-layer services and diagnostics.
- CIP Safety supports EtherNet/IP and DeviceNet communication between safety controllers, safety I/O blocks, interlock switches, light curtains, drives, and other safety devices.
- CIP Safety uses timestamps to mark the age of produced data and a production identifier so each received message arrives at the correct consumer.
- All safety transfers use Safety CRCs or checksums; data and CRC redundancy provide additional protection against corruption.
- CIP Safety packets can contain data, timestamp, time correction, and time coordination sections; no packet has all four sections.
- The Safety Network Number identifies each network path individually so each device can be uniquely identified.
- CIP Safety can coexist with CIP Motion and CIP Security.
- The CIP Safety protocol is present only in safety controllers and field devices, which prevents standard devices from posing as safety devices.

## Sources

1. [CIP Safety™ | Common Industrial Protocol | ODVA Technologies](https://www.odva.org/technology-standards/distinct-cip-services/cip-safety/) (accessed 2026-10-25)

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