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Ethernet Communication Symbols

A number of symbols in the example program are wired for TCP/IP communications with Halogen/HAL and e-control. Trace through the TCP/IP Serial Signal Flow diagram to get an overview of how these symbols work together. You will probably use these same symbols to connect to Halogen/HALs in your own programs so now let’s look at them up close.

Open the Rane_HAL.smw program file in SIMPL Windows and switch to the Program Manager. Click on the Program View pane so that it is in focus and select Expand All from the View menu. Double-click the TCP/IP Client and e-control Touchpanel symbols under the Ethernet slot of the controller to open their details dialogs. Then double-click on the Analog Equate and Serial Buffer symbols under Logic to open the details for those up.

The Port parameter for a TCP/IP Client connecting to a HAL should always be set to 4996. The same goes for a client connecting to a PC that is impersonating a HAL. Data gets sent to Halogen/HAL via the symbol’s serial TX$ input. Data from Halogen/HAL comes out the symbol’s serial RX$ output. The Connect digital input is held high so that the client keeps trying to reconnect if the connection is lost.

When a connection attempt succeeds, the outgoing analog IP_STAT signal becomes a 2. This triggers the Analog Equate symbol’s outgoing digital IP_CONNECTED signal to go high. The Serial Buffer and Serial/IO symbols are only enabled when IP_CONNECTED is high. They are disabled when the client is disconnected since both symbols only deal with strings traveling to and from Halogen/HAL.

The Serial Buffer symbol protects the program from problems that can occur when serial signals coming from Halogen/HAL are jammed (driven by multiple outputs).

Multiple symbols send strings to Halogen/HAL, so the Serial Buffer keeps them from stepping on each other. Each symbol that wants to write to the TO_DSP signal gets its own input on the Serial Buffer: TO_DSP1, TO_DSP2, TO_DSP3, etc. The Serial Buffer routes these inputs to the same TO_DSP output. If multiple inputs are issued simultaneously the output is generated in successive order. The end result is the same as giving each output a unique name and routing them to a Serial Concatenation symbol.

The strings coming from Halogen/HAL are forwarded to different symbols for processing. The Serial Buffer duplicates the signal coming from Halogen/HAL across multiple outputs. The FROM_DSP signal is forked into separate FROM_DSP1 and FROM_DSP2 signals going out to the Serial I/O and Rane HAL Level Processor symbols.

The e-control PC interface enables an XPanel to connect to the LAN that its PC host is on. The e-control Touchpanel symbol looks just like an Ethernet Touchpanel symbol in terms of ins and outs. All of the signals that are on the XPanel symbol should be applied to the same inputs and outputs on the e-control Touchpanel. This allows signals to flow out from the XPanel through the e-control over the LAN to the controller and vice versa.