Merge branch 'master' of https://github.com/robinson/gos7

README.md

@@ -1 +1,85 @@
 # gos7
+Implementation of Siemens S7 protocol in golang
+
+Overview
+-------------------
+Since years, there are tons of driver/connector in both commercial and open source that support connect to S7 family PLC devices. GoS7 is just simple missing pieces in S7 protocol which implementing in with pure Go(aka golang) with a strongly faith that low-level communication would be impelement by low-level programming language which proximity to binary and memory. 
+
+Functions
+-------------------
+AG:
+*   Read/Write Data Block (DB)
+*   Read/Write Merkers(MB)
+*   Read/Write IPI (EB)
+*   Read/Write IPU (AB)
+*   Read/Write Timer (TM)   
+*   Read/Write Counter (CT)
+*   Multiple Read/Write Area
+PG:
+*   Hot start/Cold start / Stop PLC
+*   Get CPU of PLC status
+*   List available blocks in PLC
+*   Set/Clear password for session
+*   Get CPU protection and CPU Order code
+*   Get CPU/CP Information
+*   Read/Write clock for the PLC
+Helpers:
+*   Get/set value for a byte array for types: value(bit/int/word/dword/uint...), real, time, counter
+
+Supported communication
+-----------------
+*   TCP
+*   Serial (PPI, MPI) (under construction)
+
+How to:
+----------
+following is a simple usage to connect with PLC via TCP
+```go
+const (
+	tcpDevice = "127.0.0.1"
+	rack      = 0
+	slot      = 2
+)
+// TCPClient
+handler := gos7.NewTCPClientHandler(tcpDevice, rack, slot)
+handler.Timeout = 200 * time.Second
+handler.IdleTimeout = 200 * time.Second
+handler.Logger = log.New(os.Stdout, "tcp: ", log.LstdFlags)
+// Connect manually so that multiple requests are handled in one connection session
+handler.Connect()
+defer handler.Close()
+//init client
+client := gos7.NewClient(handler)
+address := 2710
+start := 8
+size := 2
+buffer := make([]byte, 255)
+value := 100
+//AGWriteDB to address DB2710 with value 100, start from position 8 with size = 2 (for an integer)
+var helper gos7.Helper
+helper.SetValueAt(buffer, 0, value)  
+err := client.AGWriteDB(address, start, size, buffer)
+buf := make([]byte, 255)
+//AGReadDB to address DB2710, start from position 8 with size = 2
+err := client.AGReadDB(address, start, size, buf)
+var s7 gos7.Helper
+var result uint16
+s7.GetValueAt(buffer, 0, &result)	 
+
+```
+References
+----------
+- libnodave http://libnodave.sourceforge.net/
+- snap7 http://snap7.sourceforge.net/ 
+- tarm serial library https://github.com/tarm/serial
+- Simatic Open TCP/IP Communication via Industrial Ethernet from Siemens(doku)
+- SIMATIC NET FDL-Programmierschnittstelle (doku)
+- Elementary Data Types from Siemens (doku)
+
+Simatic, Simatic S5, Simatic S7, S7-200, S7-300, S7-400, S7-1200, S7-1500 are registered Trademarks of Siemens
+
+License
+----------
+https://opensource.org/licenses/BSD-3-Clause
+
+Copyright (c) 2018, robinson