Read / Write string value

TwinCAT supports two types of string variables: STRING and WSTRING.

Both types are fixed length string (the default length of STRING is 80).

Data type conversion

TwinCAT type	Python type	Comment
STRING	str	cp1252 encoding
WSTRING	str	utf-16 encoding

from py_ads_client import STRING, WSTRING, ADSClient, ADSSymbol

plc_ip = "192.168.88.20"
plc_ams_net_id = "192.168.88.20.1.1"
local_ams_net_id = "192.168.88.100.1.1"

client = ADSClient(local_ams_net_id=local_ams_net_id)
client.open(target_ams_net_id=plc_ams_net_id, target_ip=plc_ip)

string_symbol = ADSSymbol(name="GVL.stringVar", plc_t=STRING(30))
client.write_symbol(symbol=string_symbol, value="Hello World!")
string_value = client.read_symbol(string_symbol)
assert string_value == "Hello World!"

wstring_symbol = ADSSymbol(name="GVL.wstringVar", plc_t=WSTRING(30))
client.write_symbol(symbol=wstring_symbol, value="你好 World!")
wstring_value = client.read_symbol(wstring_symbol)
assert wstring_value == "你好 World!"

client.close()