Connecting Cable 6ES7368-3BB01-0AA0 6ES7 368-3BB01-0AA0 6ES7368-3BBO1-OAAO

6ES7368-3BB01-0AA0 | Siemens SIMATIC S7-300 Connecting Cable — 1m / IM 360 to IM 361 / Rack Expansion / Digital and Analog

S7-300 Multi-Rack Expansion — What This Cable Does

The 6ES7368-3BB01-0AA0 is the 1-metre expansion cable that electrically links the SIMATIC S7-300 central rack to one or more expansion (slave) racks via the IM 360/IM 361 interface module pair. In the standard S7-300 single-rack configuration, all I/O modules occupy one 18-slot or 9-slot rack with the CPU. When an application requires more I/O modules than one rack provides, the multi-rack expansion via IM 360/361 and this connecting cable adds up to three additional expansion racks.

Without this cable, there is no backplane bus between the sending IM 360 in the central rack and the receiving IM 361 in the expansion rack — the expansion racks remain electrically disconnected from the CPU.

Key Specifications

Maximum Expansion Configuration

The S7-300 IM 360/361 system supports:

Maximum 3 expansion racks: One IM 360 (central) to maximum three IM 361 modules (one per expansion rack). Each expansion rack holds up to 8 I/O modules.

Maximum total cable length: The sum of all cable lengths in the IM 360/361 bus chain must not exceed 10 metres. The 6ES7368-3BB01-0AA0 (1m) is the shortest standard length — best for tightly grouped racks in the same panel. Longer cables (2.5m, 3m, 5m) are available for racks in adjacent panels or larger panel enclosures.

Applications

High I/O count industrial automation: Production machines, conveyor systems, and process automation installations with more I/O points than one S7-300 rack accommodates — adding expansion racks via IM 360/361 and this cable extends the available I/O count without changing the CPU or programming environment.

Divided panel arrangements: Control panels where the I/O modules for different machine sections are spread across separate panel sub-sections or adjacent cabinets — expansion racks in each section, connected to the central rack's IM 360 via expansion cables.

ET 200M peripheral stations: The SIMATIC ET 200M uses the same S7-300 module format on PROFIBUS or PROFINET — the IM 360/361 expansion mechanism applies in some ET 200M multi-rack configurations.

Machine tool and process plant control: Complex machine tools with many axis, I/O, and communication modules exceeding single-rack capacity — the 6ES7368-3BB01-0AA0 expands the available module slots to accommodate all required modules.

FAQ

Q1: How many IM 361 expansion racks can be connected using IM 360/361 with the 6ES7368 cable?

The IM 360 supports maximum three expansion racks, each containing one IM 361. The connection is daisy-chained: IM 360 → IM 361 (rack 2) → IM 361 (rack 3) → IM 361 (rack 4). Each segment uses one 6ES7368 cable. Total cable length across all segments must not exceed 10 metres.

Q2: What I/O module types does 6ES7368-3BB01-0AA0 support in the expansion rack?

The expansion cable carries the full S7-300 backplane bus — supporting all S7-300 I/O module types: digital input (DI), digital output (DO), analogue input (AI), analogue output (AO), and communication modules (CP). The expansion rack I/O modules are configured in the SIMATIC STEP 7 hardware configuration tool exactly as if they were in the central rack.

Q3: Is a separate power supply required in each S7-300 expansion rack?

Yes — each expansion rack requires its own PS307 (or equivalent) 24V DC power supply module. The 6ES7368 expansion cable carries the backplane communication bus but not the 24V rack power supply. All modules in the expansion rack draw their supply from the local rack power supply. Omitting the expansion rack power supply prevents any module in that rack from operating.

Q4: What are the symptoms of a failed or disconnected 6ES7368-3BB01-0AA0 expansion cable?

The S7-300 CPU generates hardware configuration faults in STEP 7 diagnostics when expansion rack modules are unreachable — module-not-found errors, rack communication faults, or BUS_DF (bus disturbance) entries in the CPU's diagnostic buffer. All I/O in the affected expansion rack goes to the CPU's failure-state defaults (typically outputs de-energised). Reconnecting or replacing the cable and performing a CPU restart usually restores operation immediately.