Data Acquisition System Performs Fault Identification on a CT Scanner
CAS DataLoggers Engineer Terry Nagy Solves a Unique Problem
CAS DataLoggers  Engineer Terry Nagy has worked on a uniquely challenging data acquisition application which highlights the effectiveness of Delphin data loggers. A medical equipment manufacturer had a customer in a hospital who was experiencing problems with a particular CT scan machine that would reset in the middle of the procedure, which cost significant time as patients often had to be scanned again. The hospital’s other models from the same source were all functioning properly so the staff wanted to return this faulty scanner to the manufacturer, who suspected nothing was actually wrong with it. Terry explains, “A given manufacturer can build a hundred of these and one will act weird for seemingly no reason—that’s just how it is. The cause isn’t always clear since there are multiple processors and interconnected systems on this single piece of equipment.”
CAS DataLoggers supplied the manufacturer with a Delphin LogMessage 4000 Data Acquisition System , which was mounted onto the machine’s rotating scanner. Delphin LogMessage devices are specifically designed as universal data loggers, performing data acquisition using eight differential analog inputs, recording mV, mA, and thermocouple signals, with galvanic isolation of up to 100 VDC to minimize signal noise. The data logger also utilizes 28 high-precision digital inputs with two counters for frequency measurements. The Delphin LogMessage system works completely independently as a data logger for acquiring, monitoring, computing, and storing measurement data, performing scaling immediately according to the required measurement unit.
After connecting the Delphin to various circuit boards, Terry began recording the machine’s power supply voltage. The LogMessage captured this data at 10,000 points per second for each of the connected inputs. The system enables users to send their data online to a PC using the LogMessage LAN interface, which is galvanically isolated up to 100 VDC along with its power supply and all other interfaces. As with all models in the LogMessage series, the LM4000 system includes serial interfaces, an Ethernet interface, and up to 16 GB of local memory.
Professional ProfiSignal Go PC software is included with the LogMessage for measurement analysis of any type of data and online/offline monitoring and analysis. Only three steps are required to display measurement data as trends/diagrams, to analyze the data, and to evaluate offline data. Data organization and accessibility is simple by exporting as a CSV file.
After recording data for about a week, Terry and the manufacturer looked at the collected data and found that one of the connectors on the power supply had a bad crimp on one of the pins. The connection was normally stable but when the machine was in operation, vibration caused the connection to break for a fraction of a second, which reset the machine. In other words, good news, it was an easy fix.
The datalogger helped the manufacturer to identify the equipment’s fault quickly and cost-effectively, avoiding the need to scrap a very expensive piece of equipment. In similar fashion, the Delphin DAQ systems are often used in a wide variety of industrial applications such as tests and test stand automation, capturing pressure spikes and other high-speed sampling tasks, PC-independent machine monitoring, and temperature data acquisition. Using the software, these advanced systems can be switched to function with any type of sensor. For example, the system’s eight analog inputs are separately configurable and usable with all thermocouple types for precise temperature measurements. Users can also use a four-wire connection to feed Pt100 and Pt1000 sensors directly from the LogMessage device for extremely accurate temperature monitoring.
The LogMessage series is available in nine different models with eight to 30 analog inputs to suit users’ requirements, and all models are fully protected against earth loops, enabling measurements from non-isolated sources. Any number of alarm and logic channels can be defined for the analog inputs and digital channels. Users who require stronger data security over PC-based solutions can rely on the LogMessage 4000’s standard data storage capacity of up to 250 million measurements, expandable to one billion. All data is recorded with a timestamp and datestamp.
Terry Nagy comments on the suitability of the Delphin system for this tricky application: “This was definitely one of the stranger diagnostic calls I’ve had. The LogMessage and ProfiSignal software let us get started measuring immediately at the speeds necessary to flag the problem. It’s a reliable logger that can do standalone operation and the software is easy to learn if you’re new to Delphin.”