Nativ plc addressing

pyLSV2/client.py

@@ -1377,6 +1377,24 @@ def read_plc_memory(
             )
         return plc_values
 
+    def read_plc_address(self, address: str) -> Union[None, int, float, str]:
+        """
+        read from plc memory using the nativ addressing scheme of the control
+        Requires access level ``PLCDEBUG`` to work.
+
+        :param address: address of the plc memory location in the format used by the nc like W1090, M0 or S20
+
+        :raises LSV2InputException: if unknowns memory type is requested or if the to many elements are requested
+        :raises LSV2DataException: if number of received values does not match the number of expected
+        """
+
+        m_type, m_num = lm.decode_plc_memory_address(address)
+
+        if m_type is None or m_num is None:
+            raise LSV2InputException("could not translate address %s to valid memory location" % address)
+
+        return self.read_plc_memory(m_num, m_type, 1)[0]
+
     def set_keyboard_access(self, unlocked: bool) -> bool:
         """
         Enable or disable the keyboard on the control.
@@ -1629,7 +1647,7 @@ def get_file_list(self, path: str = "", descend: bool = True, pattern: str = "")
             return []
 
         if self.change_directory(path) is False:
-            self._logger.warning("could not change to directory %s" % path)
+            self._logger.warning("could not change to directory %s", path)
             return []
 
         if len(pattern) == 0:

pyLSV2/misc.py

@@ -2,12 +2,13 @@
 # -*- coding: utf-8 -*-
 """misc helper functions for pyLSV2"""
 import struct
+import re
 from datetime import datetime
 from pathlib import Path
 from typing import Union, List, Dict
 
 from . import dat_cls as ld
-from .const import BIN_FILES, PATH_SEP, ControlType
+from .const import BIN_FILES, PATH_SEP, ControlType, MemoryType
 from .err import LSV2DataException
 
 
@@ -328,3 +329,50 @@ def decode_timestamp(data_set: bytearray) -> datetime:
     """
     timestamp = struct.unpack("!L", data_set[0:4])[0]
     return datetime.fromtimestamp(timestamp)
+
+
+def decode_plc_memory_address(address: str):
+    """
+    Decode memory address location from the format used by the plc program to
+    sequential representation.
+    """
+    val_num = None
+    val_type = None
+    if result := re.fullmatch(r"(?P<m_type>[MBWDSIO])(?P<s_type>[WD])?(?P<num>\d+)", address):
+        m_type = result.group("m_type")
+        s_type = result.group("s_type")
+        num = int(result.group("num"))
+        val_num = num
+
+        if m_type == "M" and s_type is None:
+            val_type = MemoryType.MARKER
+        elif m_type == "B" and s_type is None:
+            val_type = MemoryType.BYTE
+        elif m_type == "W" and s_type is None:
+            val_num = int(val_num / 2)
+            val_type = MemoryType.WORD
+        elif m_type == "D" and s_type is None:
+            val_num = int(val_num / 4)
+            val_type = MemoryType.DWORD
+        elif m_type == "I":
+            if s_type is None:
+                val_type = MemoryType.INPUT
+            elif s_type == "W":
+                val_num = int(val_num / 2)
+                val_type = MemoryType.INPUT_WORD
+            elif s_type == "D":
+                val_num = int(val_num / 4)
+                val_type = MemoryType.INPUT_DWORD
+        elif m_type == "O":
+            if s_type is None:
+                val_type = MemoryType.OUTPUT
+            elif s_type == "W":
+                val_num = int(val_num / 2)
+                val_type = MemoryType.OUTPUT_WORD
+            elif s_type == "D":
+                val_num = int(val_num / 4)
+                val_type = MemoryType.OUTPUT_DWORD
+        elif m_type == "S" and s_type is None:
+            val_type = MemoryType.STRING
+
+    return val_type, val_num

tests/test_misc.py

@@ -5,6 +5,7 @@
 import tempfile
 from pathlib import Path
 import pyLSV2
+import pyLSV2.misc
 
 
 def test_grab_screen_dump(address: str, timeout: float):
@@ -18,3 +19,30 @@ def test_grab_screen_dump(address: str, timeout: float):
         assert local_bmp_path.stat().st_size > 1
 
     lsv2.disconnect()
+
+
+def test_plc_address_decode():
+    """test the decode function for plc memory addresses"""
+
+    assert pyLSV2.misc.decode_plc_memory_address("M0001") == (pyLSV2.const.MemoryType.MARKER, 1)
+    assert pyLSV2.misc.decode_plc_memory_address("M0") == (pyLSV2.const.MemoryType.MARKER, 0)
+    assert pyLSV2.misc.decode_plc_memory_address("M1") == (pyLSV2.const.MemoryType.MARKER, 1)
+    assert pyLSV2.misc.decode_plc_memory_address("M1234") == (pyLSV2.const.MemoryType.MARKER, 1234)
+
+    assert pyLSV2.misc.decode_plc_memory_address("B0") == (pyLSV2.const.MemoryType.BYTE, 0)
+    assert pyLSV2.misc.decode_plc_memory_address("W0") == (pyLSV2.const.MemoryType.WORD, 0)
+    assert pyLSV2.misc.decode_plc_memory_address("D0") == (pyLSV2.const.MemoryType.DWORD, 0)
+
+    assert pyLSV2.misc.decode_plc_memory_address("B4") == (pyLSV2.const.MemoryType.BYTE, 4)
+    assert pyLSV2.misc.decode_plc_memory_address("W4") == (pyLSV2.const.MemoryType.WORD, 2)
+    assert pyLSV2.misc.decode_plc_memory_address("D4") == (pyLSV2.const.MemoryType.DWORD, 1)
+
+    assert pyLSV2.misc.decode_plc_memory_address("B16") == (pyLSV2.const.MemoryType.BYTE, 16)
+    assert pyLSV2.misc.decode_plc_memory_address("W16") == (pyLSV2.const.MemoryType.WORD, 8)
+    assert pyLSV2.misc.decode_plc_memory_address("D16") == (pyLSV2.const.MemoryType.DWORD, 4)
+
+    assert pyLSV2.misc.decode_plc_memory_address("O8") == (pyLSV2.const.MemoryType.OUTPUT, 8)
+    assert pyLSV2.misc.decode_plc_memory_address("OW8") == (pyLSV2.const.MemoryType.OUTPUT_WORD, 4)
+
+    assert pyLSV2.misc.decode_plc_memory_address("I8") == (pyLSV2.const.MemoryType.INPUT, 8)
+    assert pyLSV2.misc.decode_plc_memory_address("IW8") == (pyLSV2.const.MemoryType.INPUT_WORD, 4)

tests/test_plc_read.py

@@ -134,3 +134,32 @@ def test_comapare_values(address: str, timeout: float):
             assert v1 == v2
 
     lsv2.disconnect()
+
+
+def test_plc_mem_access(address: str, timeout: float):
+    """test to see if reading via plc address and plc memory returns the same value"""
+
+    lsv2 = pyLSV2.LSV2(address, port=19000, timeout=timeout, safe_mode=False)
+    lsv2.connect()
+
+    for mem_address in [0, 1, 2, 4, 8, 12, 68, 69, 151, 300, 420]:
+        v1 = lsv2.read_plc_memory(mem_address, pyLSV2.MemoryType.DWORD, 1)[0]
+        v2 = lsv2.read_plc_address("D%d" % (mem_address * 4))
+        assert v1 == v2
+
+    for mem_address in [0, 1, 2, 4, 8, 12, 68, 69, 151, 300, 420]:
+        v1 = lsv2.read_plc_memory(mem_address, pyLSV2.MemoryType.WORD, 1)[0]
+        v2 = lsv2.read_plc_address("W%d" % (mem_address * 2))
+        assert v1 == v2
+
+    for mem_address in [0, 1, 2, 4, 8, 12, 68, 69, 151, 300, 420]:
+        v1 = lsv2.read_plc_memory(mem_address, pyLSV2.MemoryType.BYTE, 1)[0]
+        v2 = lsv2.read_plc_address("B%d" % (mem_address * 1))
+        assert v1 == v2
+
+    for mem_address in [0, 1, 2, 4, 8, 12, 68, 69, 151, 300, 420]:
+        v1 = lsv2.read_plc_memory(mem_address, pyLSV2.MemoryType.MARKER, 1)[0]
+        v2 = lsv2.read_plc_address("M%d" % (mem_address * 1))
+        assert v1 == v2
+
+    lsv2.disconnect()