The department for hardware engineering support at Rohde & Schwarz in Munich tests, integrates and deploys the CAx engineering tools for all of the company’s engineering sites. This includes customization, end user support, training, consulting and creation of libraries for ECAD, MCAD and HF-Layout. In all they provide assistance to some 100 layout designers and 200 hardware development engineers spread across 13 locations.
CR-5000 installation at Rohde & Schwarz
To create schematics, PCB and multi-board layouts and their related documentation, Rohde & Schwarz uses a comprehensive ECAD infrastructure based on CR-5000. The component selection for schematics development is supported by a dedicated component library. Schematic design is carried out in CR-5000 Design Gateway, which handles individual variants through the Variant Manager. Component placement and physical interconnect is carried out in CR-5000 Board Designer. Part of the layout creation involves the technology definition for layer and material stacks. CR-5000 includes an interface to the simulation tool Lightning, which is used to verify signal integrity of the board layouts. Manufacturing documentation is created with additional post processing and uploaded into the PDM system Teamcenter Enterprise. From there, the information is used to directly drive manufacturing execution.
The design flow in place at Rohde & Schwarz is based on Zuken’s CR-5000 PCB design suite
CR-5000 Design Gateway was introduced in 2011 together with the deployment of CR-5000 version 13. The variant process supported by Design Gateway has been set up in a way that enables the engineers at Rohde & Schwarz to define placement variants for PCBs and footprints during schematics definition. Overall, this results in a front-loading of the variant definition from layout into schematics.
The process begins with the parts master data for the single variants being created in the Rohde & Schwarz Product Structure Editor within the PDM backbone of Teamcenter Enterprise. The data is then accessed by an in-house tool, Basic Data Editor Circuit Board (BDE-CB). In BDE-CB the project is supplemented by additional information such as assembly sets (for example mounting brackets), substitute materials, solder processes, manufacturing guidelines, and parameters for the calculation of test runs. In other words, this tool manages and provides all assembly parameters that are required for manufacturing. Using another in-house tool, PD&T (Product Documentation & Transfer), product documents are generated that are transferred to the PDM system.
Schematics: the master document for all placement variants
The component and manufacturing information stored in BDECB is transferred to Design Gateway, where it provides the basis for the creation of placement variants that are defined as part of the schematic creation process. This information comprises the following:
- Placed components with different parameters per variant
- Assembly set assignments
- References for substitute material numbers.
For example, the position of a capacitor can alternatively be used to place a resistor, while the footprint on the board remains unchanged.
A design rule check during the subsequent layout definition ensures that the placed components are consistent with the assigned manufacturing process technology (such as reflow soldering).
All variants are controlled by the development engineer
“It was our objective,” stated Siegfried Doser and Robert Hahn from Rohde & Schwarz development support, “for development engineers to get the ability to define the full configuration bandwidth upfront during schematics definition, so that the schematic becomes the master document for manufacturing project execution.” In the past, the final variants were defined much later during board layout by the board designer, rather than by the development engineer who was typically unfamiliar with the layout tools used at the time.
The Bill of Materials at Rohde & Schwarz contains all placement variants in one single document, which specifies the quantity and position of components in the different individual derivatives. The manufacturing department then filters the
specific variant from this fully-defined BOM.
Migration to CR-8000
Robert Hahn and Siegfried Doser from the Rohde & Schwarz engineering support department
With the variant management process at Rohde & Schwarz building on Design Gateway, which is also the front-end module of Zuken’s new design platform CR-8000 (launched in 2011), it is reasonable to ask whether Rohde & Schwarz are planning to migrate to the next generation board layout tools of CR-8000. Hand and Doser are in close communication with users in the company’s engineering departments so they have a detailed understanding of their specific requirements. They point out the numerous considerations involved in the decision to change products. For example, whether the expected productivity gains justify the substantial migration and integration effort, as their current CR-5000 infrastructure is complemented by many applications developed in-house.
Preliminary tests at the company have confirmed that the 64-bit application CR-8000 Design Force (layout editor) not only provides a very easy-to-use, state-of-the-art user interface, but it is capable of impressive performance. With 18-layer board designs, in which all layers are filled with copper, this will provide substantial time savings.
Hahn and Doser are now carrying out comprehensive, in-depth investigations to ensure full consistency of the sophisticated engineering process at Rohde & Schwarz, with a view to rolling out Design Force capabilities in their production environment.
Overall, Rohde & Schwarz uses some 50 CR-5000 Design Gateway floating licenses for schematic development. In addition, licenses for Variant Manager, XDF Viewer, Board Designer and Lightning are used. Design Gateway is Zuken’s platform for logical circuit design and verification of single and multi-board system-level electronic designs.
Variant Manager enables the modification of individual components to meet the requirements for different product variants or requirements for international markets.
The XDF Viewer is a web browser tool that allows users to view current design data and associated errors. Board Designer provides an intuitive, integrated environment for designing PCBs, BGAs and MCMs. It serves to guide the user, via a common user interface,from floor planning through to placement, routing, analysis and manufacturing. Lightning provides a complete signal integrity analysis toolset, with Constraint Manager at its core.