Automation of Customer Drawing Formats
By: Nevagay M. Abel
Electrical Engineering Manager
System integrators are often tasked with coming up with innovative yet economical solutions to their customer’s problems. It can be something as simple as upgrading a component in a panel, to the more complex, such as integrating the latest technology with older controls systems that use outdated or obsolete hardware, software and/or communication protocols. We are always asked to do this at the lowest possible cost and in the shortest amount of time possible.
Every prospective job has its own unique set of design and build requirements, making the standardization of schematics, difficult to accomplish. Customers’ will require the system integrator to create these schematics from a design specification, a list of parts or features, hand drawn schematics or an I/O list. Typically, this process will go through several revisions as they work through the approval process with their customers, contractors and local authorities. One way to reduce cost and speed up the design process is to automate as much of the design process as possible, so when changes do come through after the initial design was submitted, the updates can be completed in a more expedient manner.
Often a customer will look to the system integrator for the development of the schematics for a project. Since each customer essentially requires a custom solution, there is less opportunity to take advantage of standardization and reuse of previous designs. Normally each sheet of the schematics is created as an individual drawing which may use a template for at least the title block or basic line numbering and power line creation. If a customer is looking for assistance in drawing design on a regular basis, and their design requirements have certain features, then there are steps that can be automated to speed up the design process.
One of the most time consuming parts of creating these custom designs is the updating of text for items such as cross-references, wire numbers, table of contents, title blocks, device ID’s, I/O points and terminal numbering. On each sheet of the schematics there can be anywhere from a couple of text points to well over one hundred in a more detailed or complex design. A set of schematics can range from a couple of sheets to more than one hundred sheets in a distributed system with hundreds of I/O. If asked to change just one item of simple text on each sheet of one hundred fifty sheet set of schematics could easily take an hour when you look at the time it takes to open the drawing, locate the text, open the attribute (assuming blocks have been used), type in the new text, close the attribute and save the drawing. Then multiply this times the number of items that must be changed on each sheet and now you’re looking at hours. If the text change could be made in a more efficient way and the sheets updated or recreated, this could offer a significant saving in time and cost. Through the use of third-party software like JTB World® AutoGen, AutoCad® and Microsoft® Excel, a systems integrator can automate some of these tasks to speed up the process if the right conditions apply.
Some of the features to look for to determine if a design is a candidate for using these automated techniques are:
• Repetitive sheets where the text may be different but the overall layout/design of the schematic sheet is the same
• Similar sheets where layer control could allow for making minor changes to the layout/design
• Large sheet sets (probably >40 sheets)
• Multiple sets of similar sheet sets
• Customer typically goes through several design approvals requiring changes to descriptions, I/O addressing, wires and terminal numbers
• A well-defined table of contents can be provided, thereby determining the templates that will be required
If it is determined that a design fits the criteria for applying the automation, the first step is to create the template designs and the required blocks associated attributes required to populate the fields. We have found that getting this part completed up front and then approved by the customer before attempting any auto-creation of the sheets saves a lot of time down the road. These templates will appear just like the final version of the sheets, but any text that will be filled out in the spreadsheet will have a holder value placed in it, thus allowing the customer to have a good feel for the final product. The system we have implemented uses a JTB World CAD Automation Tool called AutoGen. This product can create multiple sheets from a template drawing developed in AutoCad using an Excel spreadsheet we refer to as generators and the per license cost is less than $40. The program provides a spreadsheet template to get you started and can easily be modified by adding rows for additional sheets and columns for additional attributes.
Once the templates are approved, the generators can be populated with the drawing numbers, descriptions, block and attribute names required per template before any actual data is entered. The attribute data is then entered into the spreadsheet for each sheet required for the drawing set. Depending on the data that you are entering, it may be possible to automate the generation of some of that data using the formula functions with Excel. Error checking can also be implemented to check for duplicate Rack/Slot/Point addressing of I/O cards or in the terminal or wire numbers being used. Once the data has been entered into the generator, running the AutoGen program will create the individual drawing files from the templates, populated with the data entered. After checking, it is not uncommon to have to tweak the template drawings to address any overlap issue with the drawing and text or issues with the tag nomenclature of the attributes that may not have populated correctly. There may also need to be corrections made to the data in the generators, where it was entered incorrectly into the generator. Traditionally after a schematic set has been checked, each drawing that needed corrections would need to be corrected individually, even when it is a repeated error. This would again involve opening each drawing, making the necessary changes, saving and closing. However, using the templates means you only have to modify a limited number of drawings and update one spreadsheet.
Some of the other benefits we have seen from using this method are:
• Multiple generators can be used with the set of templates required. This keeps the size of the spreadsheet more manageable and allows you to create a variety of drawings sets.
• When wire numbers are part of the generator, this detail can be imported in most label systems so individual wire numbers do not need to be typed into the label maker software. This can be a considerable time saver when you require 100’s or 1000’s of wire labels for a panel. This feature can also be done with AutoCad® Electrical.
• By using the layer feature of AutoCad, it is possible to reduce the number of templates required as the layer on/off control can be done through the generator. This allows for using the same template drawing creating a number of different sheets. In one case, we were able to reduce the number of templates required for a customer due to the variation in I/O combinations and common feeds from twenty to seven, a 65% reduction in the number drawings we had to work with and maintain.
• When using a customer title block it can be modified into a block format that would then allow AutoCad® Electrical to populate the fields that are the same from sheet to sheet, while the AutoGen program can handle the fields that change from sheet to sheet, like sheet number, description and revision level, while keeping the original appearance of the block.
• If using AutoCad® Electrical, using the sigcodes in the generators and templates and providing sheet ID behind the scenes, will allow you to run the Cross Ref Update command to update the cross referencing on all the sheets.
• If using AutoCad® Electrical, if you use a block for the terminal and put this into the generator, then a terminal layout can be auto generated with terminal numbers, wire numbers, field and panel connections. This requires less time than editing each terminal block within the drawing.
Usually with custom designs there is not a lot that can be done to standardize and reduce cost with each subsequent design. However, if a design meets all, some or even just one of the criteria that was stated, it could start a conversation with your customer about what options there might be. If a customer’s current design is a candidate, with a one-time investment from them and/or the system integrator, the design time and rework hours required can be reduced and a more complete and correct set of drawings can be produced. This can save the customer lots of hours and fees in the future.