Sharp7Reactive

This is an additional library for the usage if Sharp7. It combines the S7 communication library with the power of System.Reactive.

Main features

• Completly free and ready for usage (the library is already widely used in many enterprise environments)
• Connection status observation and auto-reconnect
• Type safe and with generics
• Threadsafe (Sharp7 is basically not threadsafe)

Quick start

The example below shows you how to create and use the Sharp7Rx PLC.

using (var disposables = new CompositeDisposable())
{
    // create a new PLC
    var plc = new Sharp7Plc("10.30.3.10", 0, 2);
    disposables.Add(plc);
    
    // initialize and connect to the plc
    await plc.InitializeConnection();
    
    await plc.SetValue<bool>("DB2.DBX0.4", true); // set a bit
    var bit = await plc.GetValue<int>("DB2.int4"); // get a bit
    
    // create a nofication for data change in the plc
    var notification = plc.CreateNotification<bool>("DB1.DBX0.2", TransmissionMode.OnChange, TimeSpan.FromMilliseconds(100))
                          .Where(b => b) //select rising edge
                          .Do(_ => doStuff())
                          .Subscribe();
    disposables.Add(notification);
    
    //wait for enter before ending the program
    Console.ReadLine();
    
}

the best way to test your PLC application is running your SoftPLC locally.

Addressing rules

Sharp7Reactive uses a syntax for identifying addresses similar to official siemens syntax. Every address has the form (case unsensitive) DB<number>.<TYPE><Start>.<Length/Position>.

Example	Explaination
DB42.Int4 or DB42.DBD4	Datablock 42, 16 bit integer from bytes 4 to 5 (zero based index)
DB42.Bit0.7 or DB42.DBX0.7	Datablock 42, bit from byte 0, position 7
DB42.Byte4.25 or DB42.DBB4.25	Datablock 42, 25 bytes from byte 4 to 29 (zero based index)

Here is a table of supported data types:

.Net Type	Identifier	Description	Length or bit	Example	Example remark
bool	bit, dbx	Bit as boolean value	Bit index (0 .. 7)	Db200.Bit2.2	Reads bit 3
byte	byte, dbb, b*	8 bit unsigned integer		Db200.Byte4
byte[]	byte, dbb, b*	Array of bytes	Array length in bytes	Db200.Byte4.16
short	int, dbw, w*	16 bit signed integer		Db200.Int4
ushort	uint	16 bit unsigned integer		Db200.UInt4
int	dint, dbd	32 bit signed integer		Db200.DInt4
uint	udint	32 bit unsigned integer		Db200.UDInt4
long	lint	64 bit signed integer		Db200.LInt4
ulong	ulint, dul*, dulint*, dulong*	64 bit unsigned integer		Db200.ULInt4
float	real, d*	32 bit float		Db200.Real4
double	lreal	64 bit float		Db200.LReal4
string	string, s*	ASCII text string with string size	String length in bytes (1 .. 254)	Db200.String4.16	Uses 18 bytes = 16 + 2
string	wstring	UTF-16 Big Endian text string with string size	String length in characters (1 .. 16382)	Db200.WString4.16	Uses 36 bytes = 16 * 2 + 4
string	byte[]	ASCII string as byte array	String length in bytes	Db200.Byte4.16	Uses 16 bytes

Identifiers marked with * are kept for compatability reasons and might be removed in the future.

Performance considerations

Frequent reads of variables using GetValue can cause performance pressure on the S7 PLC, resulting in an increase of cycle time.

If you frequently read variables, like polling triggers, use CreateNotification. Internally all variable polling initialized with CreateNotification is pooled to a single (or some) multi-variable-reads.

You can provide a cycle time (delay between consecutive multi variable reads) in the Sharp7Plc constructor:

public Sharp7Plc(string ipAddress, int rackNumber, int cpuMpiAddress, int port = 102, TimeSpan? multiVarRequestCycleTime = null)

The default value for multiVarRequestCycleTime is 100 ms, the minimal value is 5 ms.

Would you like to contribute?

Yes, please!

Try the library and feel free to open an issue or ask for support.

Don't forget to star this project!