Siemens S7

This input is tailored for the S7 communication protocol, facilitating a direct connection with S7-300, S7-400, S7-1200, and S7-1500 series PLCs.

For more modern PLCs like the S7-1200 and S7-1500 the following two changes need to be done to use them:

1. "Optimized block access" must be disabled for the DBs we want to access

2. In the "Protection" section of the CPU Properties, enable the "Permit access with PUT/GET" checkbox

Configuration

input:
  s7comm:
    tcpDevice: '192.168.0.1' # IP address of the S7 PLC
    rack: 0                  # Rack number of the PLC. Defaults to 0
    slot: 1                  # Slot number of the PLC. Defaults to 1
    batchMaxSize: 480         # Maximum number of addresses per batch request. Defaults to 480
    timeout: 10             # Timeout in seconds for connections and requests. Default to 10
    disableCPUInfo: false # Set this to true to not fetch CPU information from the PLC. Should be used when you get the error 'Failed to get CPU information'
    addresses:               # List of addresses to read from
      - "DB1.DW20"     # Accesses a double word at location 20 in data block 1
      - "DB1.S30.10"   # Accesses a 10-byte string at location 30 in data block 1

Configuration Parameters

• tcpDevice: IP address of the Siemens S7 PLC.

• rack: Identifies the physical location of the CPU within the PLC rack.

• slot: Identifies the specific CPU slot within the rack.

• batchMaxSize: Maximum count of addresses bundled in a single batch request. This affects the PDU size.

• timeout: Timeout duration in milliseconds for connection attempts and read requests.

• disableCPUInfo: Set this to true to not fetch CPU information from the PLC. Should be used when you get the error 'Failed to get CPU information'

• addresses: Specifies the list of addresses to read. The format for addresses is <area>.<type><address>[.extra], where:

  • area: Specifies the direct area access, e.g., "DB1" for data block one. Supported areas include inputs (PE), outputs (PA), Merkers (MK), DB (DB), counters (C), and timers (T).

  • type: Indicates the data type, such as bit (X), byte (B), word (W), double word (DW), integer (I), double integer (DI), real (R), date-time (DT), and string (S). Some types require an 'extra' parameter, e.g., the bit number for X or the maximum length for S.

Output

Similar to the OPC UA input, this outputs for each address a single message with the payload being the value that was read. To distinguish messages, you can use meta("s7_address") in a following benthos bloblang processor.