Fault Logic is critical in automation to meet productivity goals

Does your automated production equipment stop running without giving the operator a fault message telling them why it has stopped? This is a common occurrence in manufacturing facilities with various types of automated production machinery. The cost from lost production while the operator and maintenance technicians scratch their heads trying to figure out why the machine or assembly line has stopped can be tremendous. Most of the time it’s because of inadequate or unfinished programming in the Programmable Logic Controller (PLC) and HMI that operates the machine. This can consist of lines of code, or ladder logic, which must be entered for each type of fault or condition that prevents a machine from running, or which could cause an unsafe condition. Each one of these inputs, or fault conditions should be entered into the logic along with a message on the display stating the input number which it is associated with. In the automation and machine building industry, there are time constraints to build highly complicated equipment and often times the machine is shipped without adequate runtime to discover all of the fault conditions. It can sometimes take months or years of runtime to encounter different situations which cause poor production performance.

For example, as an actuator performs work, or cycles, it’s bearings can wear and cause increased bearing friction, and thus increased current in the drive motor. With adequate fault programming, the increased drive motor currents can be detected and the operator can be alerted so that maintenance can be performed at planned downtimes versus during an emergency stoppage from a catastrophic bearing failure. And, we all know that planned preventative maintenance is much less costly then unplanned downtime.

Sometimes getting all of the fault conditions programmed into a PLC can be daunting on large assembly lines with hundreds of inputs and outputs and motor drives. But, it can pay dividends on the productivity of the equipment by reducing downtime. With Variable Frequency Drives, there can be several fault codes which can be monitored and displayed on the HMI so that equipment operators can see what is going on instead of having to wait for a technician to plug in a laptop.

The next level of fault monitoring would be to add fault condition data recording to capture and store the amount of downtime per fault condition. Over time, this will give production managers a picture of which fault conditions are causing the most downtime and help understand where design improvements in the equipment need to take place.

Morton has several years of experience in the automation industry and specializes in programming and debugging automated assembly lines, work cells, indexing tables, and almost any type of automated assembly equipment. We are trained and certified in Rockwell Automation products and can help continuously improve the productivity of the equipment in your facility and handle any electrical maintenance or construction projects for your ongoing needs. We are a team of highly trained engineers and IBEW electricians in one company that are passionate about solving problems and improving the efficiency of your operation.

Brad D. Morton

President