Opto 22 PROFIBUS Module Provides Interface to Siemen’s PLC.

It’s a common scenario for manufacturing companies: the need to expand and install more sophisticated production equipment  leads to industrial settings with a complicated mix of operating systems, hardware components and software. These disparate systems sometimes make data acquisition and analysis difficult, if not impossible.

Martindale Associates was recently contracted to solve this very problem. A large manufacturing customer needed to collect data from several different production machines, in order to perform diagnostics and introduce process improvements.

Working closely with the customer to understand their goals, Martindale Associates designed a solution centered around a high-speed communications module that provides an interface between Opto 22’s Ethernet-based SNAP PAC System and the customer’s existing serial-based PROFIBUS DP® network.

The customer now has an automated, centralized data acquisition system, providing real-time access to all production machines.

The Challenge

Martindale Associates quickly understood that the data acquisition system would need to support interfaces to serial devices, and otherwise sense and process a large variety of signal types (including voltages and currents) and also communicate with an already in place Siemens PLC. The system hardware needed be distributed throughout the facility, with custom configured data collection subsystems for each production machine. In addition, the system had to be easy to program, and have the ability to transfer data to an SQL database.

The Solution

The first decision was to standardize on Opto 22’s SNAP PAC System platform. The SNAP PAC system offers analog and digital monitoring and control capabilities, along with serial device connectivity and Ethernet connections that provided the connectivity needed to communicate data to IT systems and databases like SQL.

In order to meet the requirements and create the centralized system, Martindale Associates used Opto 22 SNAP PAC components to design and implement several data collection subsystems. Each subsystem consisted of a SNAP PAC rack, a SNAP PAC I/O processor, and various SNAP I/O modules matched to specific sensors, actuators, instrumentation and connectors on production machines.

In addition, Martindale Associates used the SNAP-SCM-PROFI module to enable communication with the Siemens PLC via the standard Profibus protocol. The Siemens PLC’s control program was modified to save  all desired data from the PLC into a group of memory addresses. The Profibus-DP port on the PLC was then configured to share those addresses in its communication. Martindale used an Opto 22 Profibus utility to configure the module for communications, and the PAC Project software to create a data collection strategy.  The strategy queries the Siemens PLC in real-time for all of its data points and also collects data from all of the individual subsystems. The OptoDataLink connectivity utility (part of the PAC Project software suite) then provides the interface needed to communicate I/O point, production and machine data to the data destination, in this case, the SQL database.

The Results

The customer is now able to collect all necessary information from their production operation in real-time. All collected data resides on a central SQL Server, allowing the customer easy access for reporting and analysis. The flexibility of the Opto 22 SNAP PAC system gives them the ability to easily make changes and add new I/O points or even all new production equipment as needed.