4/22/2020 7:27 PM | |
Joined: 9/27/2006 Last visit: 9/25/2024 Posts: 12283 Rating: (2685) |
Hello AShaker; Duris_I is quite correct, the bus speed of the whole Profbus network must be aligned with the slowest node in the configuration. To give you a simple example: Instruments that are available with a Profibus-PA interface must be connected to a Profibus-DP network either through a DP/PA coupler or a DP/PA Link. A DP/PA coupler is a protocol converter that is placed between the DP network and the instrument (flowmeter, pressure transmitter...). Now Profibus-PA uses different standards than Profibus-DP, one of which imposes a low bus speed on the PA side (this is the FISCO standard). This means that when using a DP/PA coupler, you will have to set the bus speed parameter on the Profibus-DP master to a speed of 45,45 kB.; that is the bus speed of the whole network now.This is shown in the following document, and in the screenshot below: https://support.industry.siemens.com/cs/ww/en/view/51678187 If this is unacceptable to the user, because for example he has some drives on the network that require faster communication, then you must setup a DP//PA Link ( IM 153-2 + one or more couplers) that effectively decouples the 2 networks, allowing the DP side to run at its designated speed (up to 12 MB) and the PA side to run at its slower bus speed (45,45 kB). In the case of this example, a DP/PA coupler is the "weakest" node in the Profibus network, and forces the complete network at a very slow speed. Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 04/22/2020 19:30:23Last edited by: dchartier at: 04/23/2020 15:21:07 |
|
This contribution was helpful to2 thankful Users |
Follow us on