Siemens SIMATIC NET PROFIBUS manual Transmission Delay Time

Configuring Networks

3.3Transmission Delay Time

The system reaction time of a PROFIBUS network depends largely on the following:

SThe type of system being used (single or multiple master system)

SThe maximum reaction time of the individual nodes

SThe amount of data to be transmitted

SThe bus configuration (topology, cable lengths, active network components)

The bus parameters are adapted (configured) to the particular PROFIBUS network using configuration software such as COM PROFIBUS or STEP 7.

Using optical link modules, extremely large PROFIBUS networks can be created. These allow the use of long optical fiber links and the cascading of large numbers of components. Each time the data packet passes through an OLM there is a delay.

Due to the delays caused by cables and network components and the monitoring mechanisms in the network components, the PROFIBUS network parameter “Slot Time” must be adapted to the network span, the network topology and the transmission rate.

3-22	PROFIBUS Networks SIMATIC NET
	6GK1970-5CA20-0AA1 Release 2 05/2000