ROS packages for Cognex and Siemens PLC ModBus

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Cognex In-Sight and Siemens S7 PLC Modbus Ros package and tutorial

The modbus stack provided by Génération Robots team of engineers offers a wrapper from the modbus communication to standardized ROS messages. The modbus package is based on pymodbus and is also written in Python.

This package was used in an industrial quality inspection project using the Baxter research robot interfaced with a Siemens PLC and a Cognex In-Sight camera.

baxter robot with a Cognex In-Sight camera mounted on its arm

  • The modbus package is the basic python wrapper for a modbus server and client for ROS, here you will find how to use it.
  • The package modbus_cognex_insight inherits the modbus client base class which uses specific registers. The client can send job_ids to the Cognex In-Sight camera and retrieve the results of the inspection jobs as well as barcodes decoding and strings reading. Thanks to the previous link you will find all that is needed to setup and use this wrapper with an In-Sight camera.
  • The package modbus_plc_siemens inherits the modbus client base class and changes the register size. This package allows to set the Outputs of the PLC and read its inputs. The previous link explain how to install and run this package.