Where does PROFIBUS have to be terminated?

Therefore you must observe that PROFIBUS segments are only terminated at the two segment ends and nowhere else. Any additional terminations can cause corruption of the PROFIBUS signals and network malfunction.

What is the minimum distance between 2 devices on Profibus DP?

What is the minimum distance between 2 devices on PROFIBUS DP? When the transmission speed is 1,5 Mbps or higher, it is highly recommended to have at least 1 m of cable between 2 devices. De input capacitance of both devices will be compensated by the cable in order to preserve the common impedance.

What is Profibus DP cable?

Profibus cables are automation cabling for industrial fieldbus fast-connect-type systems, particularly developed for process applications. They offer excellent electrical transmission performance for their respective Decentralised Peripherals (DP) and Process Automation (PA) applications.

What voltage is PROFIBUS DP?

Both the slave and master PROFIBUS DP test specifications state that the differential voltage between A- and B-lines shall be a minimum of 4 V and a maximum of 7 V. The signals of the A- and B-line are measured against DGND. The difference of the amplitudes shall be less than 0.5 V.

Why are termination resistors important in a PROFIBUS system?

PROFIBUS uses a differential path, which is designed to resist distortion due to external signals. However, termination resistor design is essential for the reflection effect cancellation. The termination resistance and the line-to-line impedance must match for the reflected wave attenuation.

How many device we can connect with PROFIBUS DP?

The maximum number of devices with addresses is 126. The available addresses for PROFIBUS devices are 0-126. Sometimes used for a programming tool, but available as a master or slave address. We can have a total of 126 master and slave devices on the bus including an Engineering tool.

How does Profibus DP work?

ProfiBus DP normally operates using a cyclic transfer of data between master(s) and slave(s) on an RS485 network. That is, an assigned master periodically requests (polls) each node (slave) on the network. All data communication exchanges between a master and slave originate from the master device.

How do I test my PROFIBUS cable?

Probably the best way to physically check a Profibus cable is to use the Siemens BT200 tester , which will test for Cable A/B breaks , cable A/B being swopped , cable shield breaks and incorrect terminations etc.

When would you use a termination resistor?

In electronics, you’ll encounter termination resistors when you’re working with differential pair signals, such as the RS 485. It is a simple component that ensures signal integrity on the bus, especially when high-speed transmission is involved. Furthermore, termination resistors are used to avoid signal reflections.

What is the termination option on a PROFIBUS connector?

Most Profibus connectors has a termination option. This means that you don’t have to connect your own resistor manually. You can activate or deactivate termination in the connector by flipping the switch, usually placed at the top of the connector.

Should I use PROFIBUS DP for networking?

Using a popular network like Profibus DP is a great option for networks. You will not only have a network used for many industrial applications. You will also have a lot of people with Profibus experience and a lot of resurces. The network is so widely spread out and is taught at most schools and educational institutions.

Where can I find the full specification of the Profibus cable?

You can read the full specification on the Profibus website. Further specifications of the Profibus cable are in the IEC 61784 (Previously EN 50170 chapter 8-2).

What is the loop resistance of the PROFIBUS DP cable?

The parallel connection of the two resistors make a total resistance of 110 Ω. The loop resistance of the standard Profibus DP cable is 110 Ω/km. Be aware that a standard Profibus PA cable has a loop resistance of 44 Ω/km.