Profinet to Profibus DP Gateway for Siemens S7-1200 and ABB Drives

ByHANI_AUTOMATION HANI

In modern industrial automation, it’s common to encounter devices that speak different communication protocols. A typical scenario involves a Siemens S7-1200 PLC, which natively supports Profinet, needing to control ABB variable frequency drives that only have a Profibus DP interface. This article provides a detailed, practical guide on using a Profinet to Profibus DP gateway to bridge these two networks, enabling seamless data exchange and reliable motor control.

Understanding the Integration Challenge

The Siemens S7-1200 is a compact PLC widely used in small to medium automation tasks. It features a Profinet interface for high-speed, deterministic communication. On the other hand, many ABB drives, such as the ACS series, are equipped with a Profibus DP interface, a legacy fieldbus still prevalent in many plants. Direct connection is impossible without a protocol converter. A dedicated gateway acts as a Profinet slave on one side and a Profibus DP master on the other, translating data transparently between the two networks.

This approach avoids costly hardware upgrades and leverages existing infrastructure. The gateway handles all protocol conversion internally, so the PLC sees the drives as standard Profinet I/O devices, while the drives communicate as standard Profibus slaves.

Hardware Components Required

  • Siemens S7-1200 PLC (e.g., CPU 1214C) with Profinet port
  • Profinet to Profibus DP gateway (e.g., a device that functions as PN slave and DP master)
  • ABB variable frequency drive with Profibus DP interface (e.g., ACS880 with FPBA-01 adapter)
  • Engineering tools: TIA Portal (V16 or later), Profibus configuration software (e.g., Profibus Configuration Studio), ABB DriveComposer
  • Cables: Ethernet cable for Profinet, Profibus cable with termination resistors, USB or Ethernet for gateway configuration

Step-by-Step Configuration Guide

1. Configuring the ABB Drive as a Profibus DP Slave

First, set up the drive’s communication parameters. Using the drive’s control panel or DriveComposer software, navigate to the fieldbus settings:

  • Set communication protocol to Profibus DP.
  • Assign a unique station address, e.g., 10. Ensure no other device on the bus uses this address.
  • Set the baud rate to match the gateway’s DP master setting, typically 1.5 Mbps.
  • Select a PPO type. PPO4 is common, providing 8 words of input and 8 words of output. This defines the cyclic data structure.
  • Note the I/O mapping: typically, the control word (e.g., start/stop commands) and speed reference are in the output area, while the status word and actual speed are in the input area.

2. Configuring the Gateway as Profibus DP Master

Use the gateway’s configuration tool (e.g., Profibus Configuration Studio) to set up the DP master side:

  • Create a new project and select the gateway model (e.g., PN2DPm).
  • Configure the DP master parameters: baud rate (1.5 Mbps), station address range (1–126).
  • Add the ABB drive as a slave. You can import the GSD file provided by ABB for accurate configuration, or use a generic GSD if the exact file is unavailable.
  • Set the slave address to 10 (matching the drive).
  • Define the I/O data lengths: 8 bytes output (PLC to drive) and 8 bytes input (drive to PLC). This corresponds to the PPO4 setting.
  • Save the configuration and download it to the gateway via USB or Ethernet.

3. Configuring the S7-1200 in TIA Portal

Now integrate the gateway into the Profinet network:

  • Open TIA Portal and create a project with your S7-1200 CPU.
  • In the network view, add a new Profinet device by importing the gateway’s GSD file (provided by the gateway manufacturer).
  • Drag the gateway into the network; a Profinet connection is automatically established.
  • Assign I/O addresses for the gateway’s data. For example, set input address starting at IB100 (for drive feedback) and output address starting at QB100 (for commands to drive).
  • Write the PLC program to map these I/O areas to control logic. For instance, use move instructions to set the control word and speed reference, and read the status word and actual speed.
  • Compile and download the hardware configuration and program to the PLC.

Commissioning and Troubleshooting

After powering up the system, verify the communication status:

  • Check the gateway’s LEDs: a solid Profinet light indicates connection to the PLC; a blinking Profibus light indicates active communication with the drive.
  • In TIA Portal, use the online monitoring function to observe the I/O areas (e.g., IB100–IB103 and QB100–QB103). Values should change when the drive is running.
  • On the ABB drive panel, check the communication status for any faults (e.g., F0051 communication timeout).
  • Test basic functions: start, stop, and speed reference changes. Verify that the drive responds correctly and that feedback data is accurate.

Common issues include mismatched baud rates, incorrect station addresses, or GSD file errors. Always ensure the DP bus is properly terminated at both ends.

Benefits of This Integration Approach

Using a Profinet to Profibus DP gateway offers several advantages:

  • Cost-effective: No need to replace existing Profibus drives or add expensive interface modules to the PLC.
  • Transparent data exchange: The gateway handles all protocol conversion, so the PLC programmer works with simple I/O addresses.
  • Scalability: One gateway can manage multiple DP slaves (up to 126 stations), allowing connection of several drives or other Profibus devices.
  • Reliability: Proven in industrial environments, with diagnostic LEDs and robust error handling.

Technical Specifications at a Glance

Parameter Typical Value
Profinet protocol RT (Real-Time), conformance class B
Profibus DP protocol DP-V0, DP-V1
Max DP slaves 126 (addresses 1–126)
Baud rates 9.6 kbps to 12 Mbps
I/O data size per slave Up to 244 bytes input / 244 bytes output
Configuration interface USB or Ethernet

Real-World Application Example

In a recent conveyor system retrofit, an S7-1200 controlled five ABB ACS550 drives via a single gateway. Each drive was assigned a unique DP address (10–14), and the gateway’s configuration included all five slaves with PPO4. The PLC program used a function block to scale speed references and monitor status. The system achieved a cycle time of 2 ms, well within the application’s requirements. This setup eliminated the need for a separate Profibus master module for the PLC, saving significant cost and panel space.

Conclusion: Integrating Siemens S7-1200 PLCs with ABB Profibus drives using a Profinet to Profibus DP gateway is a robust, field-proven solution. By following the configuration steps outlined above, engineers can achieve reliable communication, reduce downtime, and extend the life of existing equipment. This method is widely applicable in retrofits, machine building, and process automation where multi-protocol environments are the norm.

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