/// <summary>
/// Reads a single tag
/// </summary>
/// <param name="tag">Tag to read</param>
/// <returns>True if the read was successful</returns>
/// <remarks>This is not the preferred method of updating tag information. If you have
/// multiple tags that you want to update, use the <see cref="UpdateGroup"/> method.</remarks>
public bool ReadTag(ITag tag)
{
lock (_lockObject)
{
LogixTag lgxTag = tag as LogixTag;
if (lgxTag == null)
{
throw new ArgumentException(Resources.ErrorStrings.IncorrectArgTagType, "tag");
}
ReadDataServiceReply lgxRead = LogixServices.ReadLogixData(_session, lgxTag.Address, (ushort)lgxTag.Elements);
if (lgxRead == null || lgxRead.Data == null)
{
if (lgxRead != null)
{
lgxTag.SetTagError(lgxRead.ByteStatus);
}
lgxTag.LastError = Resources.ErrorStrings.TagNotFound + _ipAddress;
lgxTag.LastErrorNumber = (int)LogixErrors.TagNotFound;
return(false);
}
lgxTag.SetTagError(lgxRead.ByteStatus);
CIPType tagType = (CIPType)lgxRead.DataType;
byte[] temp = new byte[lgxRead.Data.Length + 2];
Buffer.BlockCopy(BitConverter.GetBytes(lgxRead.DataType), 0, temp, 0, 2);
Buffer.BlockCopy(lgxRead.Data, 0, temp, 2, lgxRead.Data.Length);
lgxTag.UpdateValue(temp);
uint offset = (uint)lgxRead.Data.Length;
if (lgxRead.Status == 0x06)
{
//We are going to have to request more data...
while (lgxRead.Status == 0x06)
{
lgxRead = LogixServices.ReadLogixDataFragmented(_session, lgxTag.Address, (ushort)lgxTag.Elements, offset);
lgxTag.SetTagError(lgxRead.ByteStatus);
tagType = (CIPType)lgxRead.DataType;
temp = new byte[lgxRead.Data.Length + 2];
Buffer.BlockCopy(BitConverter.GetBytes(lgxRead.DataType), 0, temp, 0, 2);
Buffer.BlockCopy(lgxRead.Data, 0, temp, 2, lgxRead.Data.Length);
lgxTag.UpdateValue(temp, offset);
offset += (uint)lgxRead.Data.Length;
}
}
} //End Lock
return(true);
}
private void AddOrCreateReadPacket(LogixTag tag, int idx)
{
//First we create the request...
int temp = 0;
ReadDataServiceRequest request = LogixServices.BuildLogixReadDataRequest(
tag.Address, tag.Elements, out temp);
//Now we read it from the PLC to find out if it's fragmented...
CommonPacketItem addressItem = CommonPacketItem.GetConnectedAddressItem(_parent.SessionInfo.ConnectionParameters.O2T_CID);
CommonPacketItem dataItem = CommonPacketItem.GetConnectedDataItem(request.Pack(), SequenceNumberGenerator.SequenceNumber);
EncapsReply reply = _parent.SessionInfo.SendUnitData(addressItem, dataItem);
if (reply != null)
{
//It's a good tag, let's figure out if it's fragmented...
ReadDataServiceReply rdReply = new ReadDataServiceReply(reply);
PacketMap pm = new PacketMap()
{
TagIndex = idx
};
pm.PacketIndex = new List <int>();
pm.ServiceIndex = new List <int>();
pm.Offsets = new List <uint>();
pm.NumReplies = 1;
if (rdReply.Status == 0x06)
{
//Partial read... We'll have to request more data, but first let's make this packet
request = LogixServices.BuildFragmentedReadDataRequest(tag.Address, tag.Elements,
0, out temp);
int[] status = FindPacketOrCreate(request.Pack(), (ushort)(rdReply.Data.Length + 2));
uint offset = (uint)rdReply.Data.Length;
pm.PacketIndex.Add(status[0]);
pm.ServiceIndex.Add(status[1]);
pm.Offsets.Add(0);
while (rdReply.Status == 0x06)
{
rdReply = LogixServices.ReadLogixDataFragmented(_parent.SessionInfo, tag.Address, tag.Elements,
offset);
request = LogixServices.BuildFragmentedReadDataRequest(tag.Address, tag.Elements,
offset, out temp);
status = FindPacketOrCreate(request.Pack(), (ushort)(rdReply.Data.Length + 2));
pm.PacketIndex.Add(status[0]);
pm.ServiceIndex.Add(status[1]);
offset += (uint)rdReply.Data.Length;
pm.Offsets.Add(offset);
pm.NumReplies++;
}
}
else if (rdReply.Status == 0x00 && rdReply.Data != null)
{
//Full read, create the packet...
int[] status = FindPacketOrCreate(request.Pack(), (ushort)(rdReply.Data.Length + 2));
pm.PacketIndex.Add(status[0]);
pm.ServiceIndex.Add(status[1]);
pm.Offsets.Add(0);
}
_readPackets.Add(pm);
}
}