Logo

class snap7.logo.Logo

A snap7 Siemens Logo client: There are two main comfort functions available Logo.read() and Logo.write(). This functions realize a high level access to the VM addresses of the Siemens Logo just use the form:

Notes

V10.3 for bit values V10 for the complete byte VW12 for a word (used for analog values) For more information see examples for Siemens Logo 7 and 8

__init__()

Creates a new instance of Logo

connect(ip_address: str, tsap_snap7: int, tsap_logo: int, tcpport: int = 102) → int

Connect to a Siemens LOGO server.

Notes

Howto setup Logo communication configuration see: http://snap7.sourceforge.net/logo.html

Parameters:

• ip_address – IP ip_address of server
• tsap_snap7 – TSAP SNAP7 Client (e.g. 10.00 = 0x1000)
• tsap_logo – TSAP Logo Server (e.g. 20.00 = 0x2000)

Returns:

Error code from snap7 library.

create()

Create a SNAP7 client.

db_read(db_number: int, start: int, size: int) → bytearray

This is a lean function of Cli_ReadArea() to read PLC DB.

Parameters:

• db_number – for Logo only DB=1
• start – start address for Logo7 0..951 / Logo8 0..1469
• size – in bytes

Returns:

Array of bytes

db_write(db_number: int, start: int, data: bytearray) → int

Writes to a DB object.

Parameters:

• db_number – for Logo only DB=1
• start – start address for Logo7 0..951 / Logo8 0..1469
• data – bytearray

Returns:

Error code from snap7 library.

destroy() → int

Destroy a client.

Returns:Error code from snap7 library.

disconnect() → int

Disconnect a client.

Returns:Error code from snap7 library.

get_connected() → bool

Returns the connection status

Notes

This function has a bug, that returns True when the connection

is lost. This comes from the original snap7 library.

Returns:True if connected.

get_param(number) → int

Reads an internal Logo object parameter.

Parameters:number – Parameter type number Returns:Parameter value

read(vm_address: str)

Reads from VM addresses of Siemens Logo. Examples: read(“V40”) / read(“VW64”) / read(“V10.2”)

Parameters:vm_address – of Logo memory (e.g. V30.1, VW32, V24) Returns:integer

set_connection_params(ip_address: str, tsap_snap7: int, tsap_logo: int)

Sets internally (IP, LocalTSAP, RemoteTSAP) Coordinates.

Notes

This function must be called just before Cli_Connect().

Parameters:

• ip_address – IP ip_address of server
• tsap_snap7 – TSAP SNAP7 Client (e.g. 10.00 = 0x1000)
• tsap_logo – TSAP Logo Server (e.g. 20.00 = 0x2000)

Raises:

• ValueError – if the ip_address is not an IPV4.
• Snap7Exception – if the snap7 error code is diferent from 0.

set_connection_type(connection_type: int)

Sets the connection resource type, i.e the way in which the Clients

connects to a PLC.

Parameters:connection_type – 1 for PG, 2 for OP, 3 to 10 for S7 Basic Raises:Snap7Exception – if the snap7 error code is diferent from 0.

set_param(number: int, value)

Sets an internal Server object parameter.

Parameters:

• number – Parameter type number
• value – Parameter value

Returns:

Error code from snap7 library.

write(vm_address: str, value: int) → int

Writes to VM addresses of Siemens Logo.

Parameters:

• vm_address – write offset
• value – integer

Examples

>>> write("VW10", 200) or write("V10.3", 1)