Siemens SIMATIC NET Especificações descarregar pdf (Página 64)

54 Siemens Simatic S7 Driver Online Help

How It Works

The driver polls a datablock on the device and experiences a communication timeout.

The driver attempts to re-send the request to the process hardware. If SIMATIC NET

cannot send a message, the driver marks the datablock as failed and sends a message

to the next datablock in the queue.

If SIMATIC NET can send a message, the retry proceeds, and the driver continues to

send retry message until:

• The driver poll (retries) the datablock the number of times configured for the

Retries property and still experiences a communication timeout.

• SIMATIC NET becomes unable to send a message to the device.

In either case, the driver marks the datablock as failed and sends a message to the

next datablock in the queue. Any outstanding messages for the bad device are failed

immediately. Likewise, the driver sends any messages in the queue intended for the

bad device, and all new messages, once without retries. The driver continues this

process until the communication problem with the device is resolved.

The SI7 driver also executes its QuickFail logic if SIMATIC NET cannot send a retry

message. This happens when the connection or a transaction is bad.

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Siemens SIMATIC NET Especificações Página 64