Shock and Vibration Application Brief

Elevator Vibration

The Solution

Rick Goetzl uses DADiSP, the graphic display and data management software from DSP Development Corporation, to extract and analyze data from elevator runs so that he can investigate problems. With DADiSP and his laptop data acquisition system, he can analyze ride data. He acquires the data on site while standing inside an elevator, then analyzes them back at the lab."Before we used DADiSP," Rick explains, "we were using a software package [that required us to go] through a process of manually analyzing data. This process included manually editing data files and typing lots of commands to extract the runs and analyze them." Now, he uses DADiSP and a vertical ride analyzer instead and saves time and effort.

Vertical Ride Acceleration Data

The vertical ride analyzer, developed at Montgomery Elevator, is called VeRA, and includes a field computer, three accelerometers, a battery, and miscellaneous connectors and switches. It is also compact enough to fit into a carrying case. A tri-axial accelerometer is used to acquire data from all three dimensions of vibrations on six to eight runs per elevator. 20,000 to 30,000 data points are collected per axis per session - more than 80,000 points per axis if a dozen runs are measured. Data are transferred from the field computer to PC based files. From there they are imported into DADiSP, where different analyses are conducted depending upon the types of problems that exist.

Velocity Curve Extraction

With the help of DSP staff at a Custom Training Course, Rick developed an extraction algorithm that separates data from individual elevator runs. He is currently writing more DADiSP macros to extract and analyze data automatically. For example, he might need to calculate a velocity curve on the Z-axis data and a spectrum analysis on the X- and Y- axis data in order to diagnose problems such as a misaligned rail joint in the hoistway or a bad roller guide on the elevator itself.

Custom Analysis

DADiSP's customization and storage capabilities make it possible for Rick to build a library of macros that he can use for all kinds of routine operations. Most of Rick's data analysis involves diagnosing problems in the field, but DADiSP also helps him to isolate problems that may indicate a future design change.