Features:
- An integral converter bridges the PC RS-232 interface and the differential PPI/RS-485 network side.
- Galvanic isolation separates the two communication interfaces within the cable adapter.
- Adapter switch settings align the cable operating parameters with the controller and PC connection.
Siemens 6ES7901-3CB30-0XA0 provides the physical programming path for an S7-200 connection from a computer equipped with a serial port.
Power for the converter arrives from the controller side, so a correctly wired PLC port is part of establishing the link.
The cable assembly incorporates RS-485 biasing and receiver termination instead of leaving those functions to a separate inline device.
The Siemens 6ES7901-3CB30-0XA0 SIMATIC S7-200 RS-232/PPI Multi-Master Cable may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
Siemens 6ES7901-3CB30-0XA0 SIMATIC S7-200 RS-232/PPI Multi-Master Cable Manuals,Datasheets,Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
Tracing data across the two cable interfaces
- PC Side: The computer communicates through a physical RS-232 serial interface.
- Converter Stage: The inline adapter changes the electrical signalling between RS-232 and RS-485.
- Controller Side: The PPI connector joins the RS-485 port of the S7-200 network.
- Bidirectional Link: Programming requests and controller responses follow the same converted cable path.
Supplying the inline electronics from the PLC connection
- Source: The controller-side connector provides the DC supply used by the converter.
- Isolation Barrier: The powered RS-485 side remains galvanically isolated from the PC RS-232 side.
- Current Demand: The adapter load is included when checking the available port supply.
- Link Symptom: A cable with no controller-side power cannot establish the conversion path even when the PC port is active.
Holding the differential receiver at a defined idle state
- B Conductor: A resistor biases the B line toward the internal 5 V reference.
- A Conductor: A matching resistor biases the A line toward the interface ground.
- Receiver Load: The integrated termination contributes to the minimum input impedance seen by the RS-485 network.
- Differential Decision: The receiver uses the voltage difference between A and B rather than either conductor alone.
Matching the adapter to the intended communication session
- Mode Selection: The adapter switch bank selects the supported operating mode for the cable.
- Network Rate: The chosen setting must correspond with the PPI baud rate configured at the controller.
- PC Parameters: The serial communication parameters at the computer remain consistent with the cable mode.
- Commissioning Check: Switch positions are verified before diagnosing software or network addressing.