Sample of Projects and Services



Multi-Axis tension control and precision measurement of thin film for an Aerospace customer.



Designed a 6 axis dynamic tension control and precision measurement system with integrated safety for use in a laboratory environment. Demonstrated measurement resolution to 1 micron with automated data collection of more than 1 million samples. Provided an Excel interface script to conveniently extract the data for further analysis.



GuardLogix Safety Tag Connection Faulting every few days over a Wireless radio link.



A mobile overhead stacker crane is used in an outdoor yard for product handling just prior to loading into cargo containers. Wireshark was used to capture the streaming ethernet packets and analyze the errors. The sender and receiver endpoints were functioning normally but the wireless radio transport system was found to lose packets. On a random basis of between 1 hour and 1 day, the GuardLogix controller was reporting a Safety Fault with an excessive Packet Latency of greater than 80 milliseconds. Using the ubiquitous PING command on a laptop, packet Latency was reported as less than 20 milliseconds but is only a one time measurement. Single packet network testing using PING did not reveal the actual problem on the network. A much more comprehensive statistical analysis was required.


An industry standard RFC 2544 test performed for 1 hour and conclusively demonstrated the source of the problem. The wireless radio was normally transmitting packets with a Latency of ~30 milliseconds but infrequently the Latency would increase up to 173 millisecond and cause the Guardlogix controller to correctly fault due to the late arrival of the Safety data.



Motor Parameter Identification, Drive Optimization and Testing of a High Power, High Speed Square Frame Spindle Motor



Customer requested assistance to specify a compatible drive with a custom winding, water cooled spindle motor to meet the production performance requirements in the machine application. Several OEM drive vendors failed to successfully operate the motor and would quickly nuisance fault. Tested the motor and quickly determined the motor data sheets provided by the OEM were incorrect due to a technical issue. Contacted the OEM and resolved the technical error. Specified a compatible motor control drive and demonstrated full production performance requirements on a dynamometer. Then installed the drive on the machine tool and again demonstrated full production performance requirements and eliminated the nuisance faults.



Random machine shutdowns after electricians installed new network cables.



A machine retrofit was performed by a group of electricians on a large industrial machine with multiple remote I/O racks and AC motor drives. The communication protocol was Ethernet/IP to all devices in the system. During commissioning, the Guardlogix controller was reporting intermittent communication errors to each of the remote I/O racks.


The network physical media was carefully inspected and a number of issues were identified. The most serious issue is specific to the compatibility of the plugs and jacks. To insure a reliable connection, the mating Ethernet Plugs and Jacks must both meet the specific mechanical specifications outlined in TIA‐1096 ‐ Connector Requirements for Connection of Terminal Equipment. The field installed plugs failed the contact height GO‐NO‐GO test. Further investigation determined the electricians had used the incorrect tool for crimping the connector body. The required crimp tool from the connector OEM was provided to the electricians along with specific assembly instructions. All of the recently installed connectors were replaced and tested with a GO‐NO‐GO test tool. Then each cable assembly was tested using a cable certifier to a minimum of 100baseTX per TIA 568.C requirements.



High Power Common DC Bus and Dual Mode AC Line Regenerative Drive and Motor Control System



Application: High speed dynamometer for testing avionics systems. A pair of 120HP at 6500rpm precision balanced custom motors with AC regenerative and Utility power loss braking capability of high inertia loads.



Ethernet Cable Certified Test Report for Commissioning A New Machine



Commissioned a large automation machine that included 50 network cables of up to 90 meters long. Each network cable was custom assembled by onsite electricians. Each network cable assembly was tested using a cable certifier to a minimum of 100baseTX per TIA 568.C requirements to insure satisfactory and reliable operation of the automation equipment. Three out of the 50 cables required re-work to meet the specifications.



Automated Manufacturing Equipment Including Safety Control system for Aerospace Customer



Application: Designed and developed a low cost, easy to manufacture PAC based control system for use in a high volume production environment where collaborative machine robotics and automation was required. Provided an innovative and low cost safety control system to meet the risk assessment requirements.



AC Drive Failure Analysis



In-the-field product failure investigation if an I/O module installed in a motor drive. A total of 6 I/O modules failed among a population of 5 motor drives. Collected site specific measurements, recreated damaging physical anomalies in the lab and published the findings in a failure analysis and solution report. Provided detailed failure and cause analysis to the satisfaction of all stakeholders. Eliminated the finger pointing with a concise and definitive solution consisting of adding a RC snubber to a motor contactor coil in the electrical enclosure.



Elimination of Machine Structural Resonance Improves Production Machine Placement Accuracy



A customer observed a servo motor driven precision placement machine was not able to accurately and repeatedly align production parts into a machine nest, causing machine jams several times an hour. Their own analysis of the PAC program and servo motion performance did not reveal any problems and should have achieved the placement accuracy required.


Further testing of the machine program and servo motor feedback position information confirmed the customer’s conclusion that the motion system performing properly and should not exhibit the machine jams. The machine structure supporting the servo motor and linear actuator was analyzed using a Dynamic Signal Analyzer and Accelerometer. A resonance with very little damping was identified at 13 hz and coincided with the shape of the deceleration motion profile required to meet the production requirements. The resonance caused an error in locating the part of more than 1.3 mm, enough to jam the machine. As the motion profile could not be changed, the machine structure was modified to eliminate the 1st modal shape resonance. The machine was placed back into production and the frequent machine jams were eliminated.



Custom Laboratory Stirrer for the Pulp and Paper Industry



This laboratory product is a controllable power source fo precisely operate brushtype, DC servomotors. Configured as a controlled velocity system, the controller provides an analog voltage signal proportional to the desired motor velocity. It is a 20 kHz pulse-width modulation (PWM), switching type amplifier that eliminates audible noise and system power losses. Motor speed is precisely controlled by a 16 bit digital controller, even with varying loads over a wide operating speed range. Automatic current foldback with speed reduction is employed to protect the electronics and motor from damaging over-current conditions. The custom designed sheet metal enclosure and operator interface is specifically designed for rough service in a Laboratory environment.



EM Interface, LLC



Tel : 425-417-0565
email: jeffk@eminterface.com
PO Box 1799, Duvall, WA 98019