private int NegotiatePduLength()
{
int Length;
// Set PDU Size Requested
S7.SetWordAt(S7_PN, 23, DefaultPduSizeRequested);
// Sends the connection request telegram
SendPacket(S7_PN);
if (LastError == 0)
{
Length = RecvIsoPacket();
if (LastError == 0)
{
// check S7 Error
if ((Length == 27) && (PDU[17] == 0) && (PDU[18] == 0)) // 20 = size of Negotiate Answer
{
// Get PDU Size Negotiated
_PDULength = S7.GetWordAt(PDU, 25);
if (_PDULength > 0)
{
return(0);
}
else
{
LastError = errISONegotiatingPDU;
}
}
else
{
LastError = errISONegotiatingPDU;
}
}
}
return(LastError);
}
public int ReadSZL(int ID, int Index, S7Szl SZL)
{
int Length;
int DataSZL;
int Offset = 0;
Boolean Done = false;
Boolean First = true;
byte Seq_in = 0x00;
int Seq_out = 0x0000;
LastError = 0;
SZL.DataSize = 0;
do
{
if (First)
{
S7.SetWordAt(S7_SZL_FIRST, 11, ++Seq_out);
S7.SetWordAt(S7_SZL_FIRST, 29, ID);
S7.SetWordAt(S7_SZL_FIRST, 31, Index);
SendPacket(S7_SZL_FIRST);
}
else
{
S7.SetWordAt(S7_SZL_NEXT, 11, ++Seq_out);
PDU[24] = (byte)Seq_in;
SendPacket(S7_SZL_NEXT);
}
if (LastError != 0)
{
return(LastError);
}
Length = RecvIsoPacket();
if (LastError == 0)
{
if (First)
{
if (Length > 32) // the minimum expected
{
if ((S7.GetWordAt(PDU, 27) == 0) && (PDU[29] == (byte)0xFF))
{
// Gets Amount of this slice
DataSZL = S7.GetWordAt(PDU, 31) - 8; // Skips extra params (ID, Index ...)
Done = PDU[26] == 0x00;
Seq_in = (byte)PDU[24]; // Slice sequence
SZL.LENTHDR = S7.GetWordAt(PDU, 37);
SZL.N_DR = S7.GetWordAt(PDU, 39);
SZL.Copy(PDU, 41, Offset, DataSZL);
Offset += DataSZL;
SZL.DataSize += DataSZL;
}
else
{
LastError = errS7FunctionError;
}
}
else
{
LastError = errS7InvalidPDU;
}
}
else
{
if (Length > 32) // the minimum expected
{
if ((S7.GetWordAt(PDU, 27) == 0) && (PDU[29] == (byte)0xFF))
{
// Gets Amount of this slice
DataSZL = S7.GetWordAt(PDU, 31);
Done = PDU[26] == 0x00;
Seq_in = (byte)PDU[24]; // Slice sequence
SZL.Copy(PDU, 37, Offset, DataSZL);
Offset += DataSZL;
SZL.DataSize += DataSZL;
}
else
{
LastError = errS7FunctionError;
}
}
else
{
LastError = errS7InvalidPDU;
}
}
}
First = false;
}while (!Done && (LastError == 0));
return(LastError);
}
public int WriteArea(int Area, int DBNumber, int Start, int Amount, byte[] Data)
{
int Address;
int NumElements;
int MaxElements;
int TotElements;
int DataSize;
int IsoSize;
int Length;
int Offset = 0;
int WordSize = 1;
LastError = 0;
// If we are addressing Timers or counters the element size is 2
if ((Area == S7.S7AreaCT) || (Area == S7.S7AreaTM))
{
WordSize = 2;
}
MaxElements = (_PDULength - 35) / WordSize; // 18 = Reply telegram header
TotElements = Amount;
while ((TotElements > 0) && (LastError == 0))
{
NumElements = TotElements;
if (NumElements > MaxElements)
{
NumElements = MaxElements;
}
DataSize = NumElements * WordSize;
IsoSize = Size_WR + DataSize;
// Setup the telegram
Array.Copy(S7_RW, 0, PDU, 0, Size_WR);
// Whole telegram Size
S7.SetWordAt(PDU, 2, IsoSize);
// Data Length
Length = DataSize + 4;
S7.SetWordAt(PDU, 15, Length);
// Function
PDU[17] = (byte)0x05;
// Set DB Number
PDU[27] = (byte)Area;
if (Area == S7.S7AreaDB)
{
S7.SetWordAt(PDU, 25, DBNumber);
}
// Adjusts Start and word length
if ((Area == S7.S7AreaCT) || (Area == S7.S7AreaTM))
{
Address = Start;
Length = DataSize;
if (Area == S7.S7AreaCT)
{
PDU[22] = S7WLCounter;
}
else
{
PDU[22] = S7WLTimer;
}
}
else
{
Address = Start << 3;
Length = DataSize << 3;
}
// Num elements
S7.SetWordAt(PDU, 23, NumElements);
// Address into the PLC
PDU[30] = (byte)(Address & 0x0FF);
Address = Address >> 8;
PDU[29] = (byte)(Address & 0x0FF);
Address = Address >> 8;
PDU[28] = (byte)(Address & 0x0FF);
// Length
S7.SetWordAt(PDU, 33, Length);
// Copies the Data
Array.Copy(Data, Offset, PDU, 35, DataSize);
SendPacket(PDU, IsoSize);
if (LastError == 0)
{
Length = RecvIsoPacket();
if (LastError == 0)
{
if (Length == 22)
{
if ((S7.GetWordAt(PDU, 17) != 0) || (PDU[21] != (byte)0xFF))
{
LastError = errS7DataWrite;
}
}
else
{
LastError = errS7InvalidPDU;
}
}
}
Offset += DataSize;
TotElements -= NumElements;
Start += NumElements * WordSize;
}
return(LastError);
}
public int ReadArea(int Area, int DBNumber, int Start, int Amount, byte[] Data)
{
int Address;
int NumElements;
int MaxElements;
int TotElements;
int SizeRequested;
int Length;
int Offset = 0;
int WordSize = 1;
LastError = 0;
// If we are addressing Timers or counters the element size is 2
if ((Area == S7.S7AreaCT) || (Area == S7.S7AreaTM))
{
WordSize = 2;
}
MaxElements = (_PDULength - 18) / WordSize; // 18 = Reply telegram header
TotElements = Amount;
while ((TotElements > 0) && (LastError == 0))
{
NumElements = TotElements;
if (NumElements > MaxElements)
{
NumElements = MaxElements;
}
SizeRequested = NumElements * WordSize;
// Setup the telegram
Array.Copy(S7_RW, 0, PDU, 0, Size_RD);
// Set DB Number
PDU[27] = (byte)Area;
// Set Area
if (Area == S7.S7AreaDB)
{
S7.SetWordAt(PDU, 25, DBNumber);
}
// Adjusts Start and word length
if ((Area == S7.S7AreaCT) || (Area == S7.S7AreaTM))
{
Address = Start;
if (Area == S7.S7AreaCT)
{
PDU[22] = S7WLCounter;
}
else
{
PDU[22] = S7WLTimer;
}
}
else
{
Address = Start << 3;
}
// Num elements
S7.SetWordAt(PDU, 23, NumElements);
// Address into the PLC (only 3 bytes)
PDU[30] = (byte)(Address & 0x0FF);
Address = Address >> 8;
PDU[29] = (byte)(Address & 0x0FF);
Address = Address >> 8;
PDU[28] = (byte)(Address & 0x0FF);
SendPacket(PDU, Size_RD);
if (LastError == 0)
{
Length = RecvIsoPacket();
if (LastError == 0)
{
if (Length >= 25)
{
if ((Length - 25 == SizeRequested) && (PDU[21] == (byte)0xFF))
{
Array.Copy(PDU, 25, Data, Offset, SizeRequested);
Offset += SizeRequested;
}
else
{
LastError = errS7DataRead;
}
}
else
{
LastError = errS7InvalidPDU;
}
}
}
TotElements -= NumElements;
Start += NumElements * WordSize;
}
return(LastError);
}