diff --git a/lib/GE_SRTP.py b/lib/GE_SRTP.py
index 7727e9e..a90029c 100644
--- a/lib/GE_SRTP.py
+++ b/lib/GE_SRTP.py
@@ -110,7 +110,38 @@ def closeConnection(self):
         except Exception as err:
             print("Exception:" + str(err))
 
+    ###########################################################
+    # Generates command string to send to PLC for writing
+    # registers. Expects format of R#### etc.
+    # Returns: Bytearray for sending via socket.
+    ###########################################################
+    def writeSysMemory(self, reg, val):
+        if not re.search('%*(R|AI|AQ|I|Q)\d+',reg):
+            raise Exception("Invalid Register Address! (" + reg + ").")
 
+        try:
+            # Make copy of generic base message
+            tmp = GE_SRTP_Messages.BASE_MSG.copy()
+            tmp[42] = GE_SRTP_Messages.SERVICE_REQUEST_CODE["WRITE_SYS_MEMORY"]
+            # Update for type of register
+            tmp[43] = GE_SRTP_Messages.MEMORY_TYPE_CODE[re.search('(R|AI|AQ|I|Q)',reg)[0]]
+            # 0 based register to read
+            address = int(re.search('\d+',reg)[0]) - 1
+            tmp[44] = int(address & 255).to_bytes(1,byteorder='big')        # Get LSB of Word
+            tmp[45] = int(address >> 8 ).to_bytes(1,byteorder='big')        # Get MSB of Word
+            # Update for width
+            tmp[46] = b'\x01'               # DANGER - TODO make dynamic for different data types.
+            tmp[47] = b'\x00'
+            # Value
+            tmp[48] = int(int(val) & 255).to_bytes(1,byteorder='big')        # Get LSB of Word
+            tmp[49] = int(int(val) >> 8 ).to_bytes(1,byteorder='big')        # Get MSB of Word
+            bytes_to_send = b''.join(tmp)
+            # Send to PLC, Read Response back as memory value (string type)
+            response = self.sendSocketCommand(bytes_to_send)
+            return(GeSrtpResponse(response))
+        except Exception as err:
+            print(err)
+            raise Exception("Failure reading PLC or Register from PLC. Abort")
 
     ###########################################################
     # Generates command string to send to PLC for reading
@@ -236,4 +267,4 @@ def printLimitedBin(self, pre_msg, msg, start=7, end=7):
             if iter_len - idx <= end:
                 hex_resp_end += " {:02x}".format(x)
             
-        print("{}{}...{} (Only Displaying {} of {} bytes)".format(pre_msg, hex_resp_start, hex_resp_end, start + end, len(msg)))
\ No newline at end of file
+        print("{}{}...{} (Only Displaying {} of {} bytes)".format(pre_msg, hex_resp_start, hex_resp_end, start + end, len(msg)))