andrewjfox

Hi,

I've got a query regarding memory array and sharing between sequences running in seperate threads.

I'd like to have Sequence1 putting data into an array, and Sequence2 pulling it out ie FIFO. I was thinking of implementing a fifo array with head and tail indexes where the "putting" sequence uses the head and the "pulling" sequence uses the tail index.

1. Is it safe to use the arrays like this, are they thread-safe?

2. I haven't seen a builtin "fifo" structure so will have to implement in code which I've done many times but not in DF. Do you have any tips/pitfalls to watch out for?

Background info
My application involves pulling data from a remote TCP device, putting a time stamp on it and putting it into an array, for another sequence to process. I need the putting seq to be fast since it's the one putting time stamps on incoming data and I want them to be as real time as possible. The processing sequence does a bunch of sorting, processing and manipulating then stores the required data to file, so this can be a bit slower. Currently I'm using a basic semaphore flag to control which sequence gets access, however I don't think it's the most effective way since it means the putting sequence may have to wait for the processing sequence to relinquish the flag.

Regards
Andrew

Hi ,

I've been using objects for ports and devices in an existing project but am still getting some behaviour which I don't understand

I am trying to close and -reopen a ethernet connection as follows

//Instatiate objects, and open connections

define CTRL_PORT = 0
define RADIO_PORT = 1

class DeviceObj
   local iDevice
   local RxBuff  
   local State
  
   function OnCreate()
	  iDevice = new(CCommDevice)
	  State = DEVICE_STATE_CLOSED
   endfunction
  
endclass

global MyDevice
global MyPort

for(private i=0,i<MAX_READERS,i++)
   MyPort[i*2 + CTRL_PORT] = new(CCommEthernet)
   MyDevice[i*2 + CTRL_PORT] = new(DeviceObj) 
   MyPort[i*2 + RADIO_PORT] = new(CCommEthernet)
   MyDevice[i*2 + RADIO_PORT] = new(DeviceObj)
  OpenConnection(i)
endfor

// functions to open & close connections

function OpenConnection(ReaderIndex)
  
   private pDevice
   private pPort
  
   try
	  pDevice = MyDevice[ReaderIndex*2 + CTRL_PORT]	 
	  if(pDevice.State == DEVICE_STATE_CLOSED)
		 pPort = MyPort[ReaderIndex*2 + CTRL_PORT]	 
		 pPort.Address = strAddressBase + DoubleToStr(DeviceAddress[ReaderIndex])
		 pPort.Port = CPORT
		 pPort.Timeout = 1000
		
		 pDevice.iDevice.PortObject = MyPort[ReaderIndex*2 + CTRL_PORT]
		 pDevice.iDevice.ProtocolName = "NULL Protocol"
		 pDevice.iDevice.InitComm()
		 pDevice.State = DEVICE_STATE_OPEN
	  endif
	  pDevice = MyDevice[ReaderIndex*2 + RADIO_PORT]
	  if(pDevice.State == DEVICE_STATE_CLOSED)
		 pPort = MyPort[ReaderIndex*2 + RADIO_PORT]	
		 pPort.Address = strAddressBase + DoubleToStr(DeviceAddress[ReaderIndex])
		 pPort.Port = RPORT
		 pPort.Timeout = 1000
		
		 pDevice.iDevice.PortObject = MyPort[ReaderIndex*2 + RADIO_PORT]
		 pDevice.iDevice.ProtocolName = "NULL Protocol"
		 pDevice.iDevice.InitComm()
		 pDevice.State = DEVICE_STATE_OPEN
	  endif
   catch()
	  Event.AddValue(Format("Error: Rdr%02d, ",ReaderIndex)+strLastError)
   endcatch
endfunction


function CloseConnection(ReaderIndex)
  
   private pDevice
   private pPort
   //try
	  pDevice = MyDevice[ReaderIndex*2 + CTRL_PORT]
	  pPort = MyPort[ReaderIndex*2 + CTRL_PORT]
	 
	  pPort.Address = ""
	  pPort.Port = 0
	  pDevice.iDevice.PortObject = MyPort[ReaderIndex*2 + CTRL_PORT]
	  pDevice.iDevice.InitComm()
	  pDevice.State = DEVICE_STATE_CLOSED
	 
	  pDevice = MyDevice[ReaderIndex*2 + RADIO_PORT]
	  pPort = MyPort[ReaderIndex*2 + RADIO_PORT]
	 
	  pPort.Address = ""
	  pPort.Port = 0
	  pDevice.iDevice.PortObject = MyPort[ReaderIndex*2 + RADIO_PORT]
	  pDevice.iDevice.InitComm()
	  pDevice.State = DEVICE_STATE_CLOSED
	 
   //catch()
   //   Event.AddValue(Format("Error: Rdr%02d, ",ReaderIndex)+strLastError)
   //endcatch 
endfunction

When I call the CloseConnection function I get an error at the InitComm() function

CloseConnection(0)
C1000 Channel or function not found: CloseConnection Line 15: Line 1

My understanding is that the InitComm() call should be successful regardless of whether connection is open /closed. Do you have any ideas for me to try?

Also I tried including the port object in my device object

class DeviceObj

   local iDevice
   local RxBuff  
   local State
  
   function OnCreate()
  iDevice = new(CCommDevice)
  State = DEVICE_STATE_CLOSED
   endfunction
  
endclass



Regards
Andrew

Hi,

I'm having some trouble with the various data types. Although variables, channels and vchannels work similarly (in theory) I'm finding certain subtle differences and can't get the right type for what I want.

application:
I'm storing arrays as they come in over a network to a variable for later processing.
eg
Data.AddValue({{128,1,3,5,7}})
Data.AddValue({{129,2,4,6,8}})

Data = {{129,2,4,6,8},{128,1,3,5,7}}

then in processing loop the code looks for data with bit 7 set (data dirty bit) in first element, and clears this bit when data has been processed.

if(TestBit(Data[0][0],7))
Data[0][0] = ClearBit(Data[0][0],7)
// do some processing on Data
endif

The processing loop also uses the timestamp of each array, Data.Time[0], as part of the processing

Problem:
- If Data is V type, then AddValue sets the time of all previously added arrays in history to the same value, so I can't use the timestamps to process the data
- If Data is channel, then trying to change an existing value (Data[0][0]) is the same as AddValue, so adds new entry with incorrect data, instead of changing the existing data at [0][0]
- If data is variable then, again, trying to change a single element Data[0][0] stuffs up the entire history

I'd like to be able to add arrays to a channel/variable, and be able to go through the history and change individual elements. Is this possible using the functions AddValue etc, or do I need to manually manipulate a standard array? I only want a history of about 100 arrays

Regards
Andrew