# Siemens S7+ Connection Properties

## `host` (string, required)

Defines the IP address or DNS hostname of the target PLC.

Example: `"192.168.20.60"`

## `port` (integer, required)

Defines the TCP port of the PLC communication interface. Siemens S7 devices typically listen on port 102.

Default: `102`

Example: `102`

Additional restrictions:

* Minimum: `1`
* Maximum: `65535`

## `rack` (integer, required)

Defines the hardware rack index that is used in Siemens SIMATIC addressing.

Default: `0`

Example: `0`

## `slot` (integer, required)

Defines the slot index of the CPU module inside the hardware rack that is used in Siemens SIMATIC addressing.

Default: `1`

Example: `1`

## `DevNr` (integer)

Defines the identifier that is used to distinguish multiple PLC connections. Each connection inside a service commissioning file must use a unique number between 0 and 255.

Default: `0`

Examples: `0`, `1`, `2`

Additional restrictions:

* Maximum: `255`

## `ConnType` (string, enum)

Selects the addressing mode. TCPIP uses absolute byte and bit addresses. TCPIPTIA loads TIA symbols and enables symbolic addressing (TIA Portal).

This element must be one of the following enum values:

* `TCPIP`
* `TCPIPTIA`

Default: `"TCPIPTIA"`

Examples: `"TCPIP"`, `"TCPIPTIA"`

## `isOptimized` (boolean)

Enables request bundling to reduce the number of individual read/write requests. This affects communication behavior only, not TIA datablock optimization in the PLC.

Default: `false`

Examples: `true`, `false`

## `connectionTimeout` (integer)

Defines the maximum time (in milliseconds) that Connectware waits during initial connection and symbol loading. Large TIA Portal projects may require more than 30000 ms (default). Increase this value if the connection fails before all symbols are loaded.

Default: `30000`

Examples: `30000`, `60000`

Additional restrictions:

* Minimum: `1000`

## `operationTimeout` (integer)

Defines the time limit (in milliseconds) for each read or write operation. Lower values report failures more quickly. Higher values are recommended for large arrays or networks with higher latency.

Default: `5000`

Examples: `5000`, `10000`

Additional restrictions:

* Minimum: `-1`

## `healthCheckInterval` (integer)

Defines the interval (in milliseconds) between periodic health check probes. Set to 0 to disable health monitoring. Longer intervals reduce PLC load, shorter intervals detect outages more quickly.

Default: `10000`

Examples: `10000`, `30000`, `60000`, `0`

## `healthCheckTimeout` (integer)

Defines the timeout (in milliseconds) for each health check operation. This value should remain lower than `operationTimeout` so that broken connections are detected early.

Default: `10000`

Examples: `10000`, `5000`

Additional restrictions:

* Minimum: `100`

## `healthCheckFailureThreshold` (integer)

Defines the number of consecutive failed health checks before Connectware disconnects and starts a reconnect cycle.

Default: `3`

Examples: `3`, `5`

Additional restrictions:

* Minimum: `1`

## `preOperationConnValidation` (boolean)

Verifies PLC responsiveness before each operation. This improves reliability but adds an additional round trip. Only use for critical data paths.

Default: `false`

Examples: `false`, `true`

## `useSymbolCacheFile` (boolean)

Enables caching of TIA symbol information to a file so that subsequent connections start faster (S7+/TIA only).

Default: `false`

Examples: `true`, `false`

## `symbolCacheFilePath` (string)

Specifies a custom path for the symbol cache file. This setting is only applied when `useSymbolCacheFile` is set to `true`. If left empty, the default path `/var/tmp/plc_{host}_{port}_dev{deviceNr}.agl` is used.

Default: `""`

Examples: `"/var/tmp/plc_192.168.10.60_102_dev0.agl"`, `""`

## `connectionStrategy` (object)

Controls how long Connectware waits between repeated connection attempts when the PLC is unreachable. Delays grow according to an exponential backoff pattern until the maximum delay is reached.

Properties of the `connectionStrategy` object:

#### `initialDelay` (integer)

Delay of the first connection retry (in milliseconds). Later retries increase this delay using the `incrementFactor`.

Default: `5000`

Examples: `5000`, `3000`, `1000`

Additional restrictions:

* Minimum: `1000`

#### `maxDelay` (integer)

Upper bound for retry delay (in milliseconds). Once this value is reached, all further retries wait this long between attempts.

Default: `30000`

Examples: `30000`, `60000`

Additional restrictions:

* Minimum: `5000`

#### `incrementFactor` (integer)

Multiplier that increases the retry delay after each failed attempt until it reaches `maxDelay`. For example, with `initialDelay` 1000 and `incrementFactor` 2 the delays are 1000, 2000, 4000, 5000.

Default: `2`

Examples: `2`, `3`

Additional restrictions:

* Minimum: `2`