Siemens SIMATIC NET Especificações descarregar pdf (Página 15)

Chapter 1. First-time Users 5

In the SI7 driver, you also need to configure a SIMATIC NET API timeout value

called the global timeout. Like the driver’s reply timeout, the global timeout expires

whenever the process hardware has not responded to a request.

The difference between the two timeouts is that the reply timeout is used by the SI7

driver and the global timeout is not. The global timeout is SIMATIC NET’s message

timeout. For more information about global timeouts, refer to your Siemens

documentation.

NOTE: Global timeouts for Profibus and Industrial Ethernet do not behave

consistently. For this reason, we recommend that you configure the reply timeout to

be longer than the global timeout.

See Also

Understanding Device Timing Properties: Reply Timeout, Retry, and Delay Time

How Do Retries Work?

Whenever a driver times out, it re-sends its request to the process hardware if it can.

The Siemens’ communication software, SIMATIC NET, determines whether or not it

is able to send another request. If it is, the retry is sent. The process of timing out and

re-sending a request for data continues until the driver receives the data or the number

of retries is exhausted.

The number of retries defines the number of times you want to re-send (retry) a

request for data before assuming the device is unavailable. The driver re-sends data

after each timeout unless:

• The driver exhausts all retries.

• SIMATIC NET determines it is not able to re-send data.

Once either of these conditions occurs, the driver does not send another request for

that datablock’s data until the delay time expires. This time interval defines how long

the driver waits before requesting data again.

You can specify the number of retries in the Retries field of your driver configuration

program. In most 7.x drivers, it is a device property.

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