SC11 Basic System Product Description

There was a time when conducting accurate site surveys used to involve a mass of complex, bulky and difficult-to-use equipment. Based on a laptop computer and operating under Windows 95/98/Me/NT/2000/XP, the SC11 has revolutionized site surveys. It is a fully portable tool for measurement and analysis of ambient AC magnetic fields, vibrations and acoustic levels in one compact system. The system is based on a laptop personal computer, a three axis magnetic field sensor, an accelerometer and a sound level meter. An optional flux gate magnetometer measures DC magnetic fields. There is also the ability to attach extra sensors if so desired.

The software suite consists of three virtual instruments, an oscilloscope, a spectrum analyzer and a chart recorder. In each case the information is displayed graphically on the laptop screen and the data can be exported to spreadsheet programs for further processing and hard copies can be made on industry standard printers.

The SC11 has four measurement channels, three assigned to the axes of the magnetic field sensor and one auxiliary. The auxiliary channel is designed to be driven from the accelerometer, the sound level meter, the magnetometer or other signals such as the video output of an SEM running in spot mode.

The SC11 is designed to be fully portable, fitting neatly into a carrying case which is supplied. The system is powered from the laptop so that operation without a main power connection is possible. The sound level meter and magnetometer have their own batteries. The complete system is accurate, easy to operate with a minimum of training and produces user friendly results.

SC11 Applications

Surveys
Designed with electron microscope and E-beam vendors and consultants in mind the SC11 provides all the features needed for site surveys in one simple, easy to use package.

The SC11 is ideal for making accurate surveys of magnetic fields, vibrations and acoustic levels. Before installing equipment such as a scanning electron microscope (SEM) it is advisable to survey the location first. In an environment where there are many pieces of equipment, power cables and air handling units it is difficult to judge in advance whether there could be problems. You can use the SC11 system to survey the magnetic field, vibration and sound levels to make sure that they are within specification at the proposed site for the SEM. With the latest software, you can load the SEM specifications into the spectrum analyzer for quick comparison with your measurements. The industry standard 1/3 octave analysis feature is useful in this application.

Trouble shooting
The magnetic field sensor is very sensitive, so it allows you to pin-point sources of magnetic fields, such as transformers, motors and poorly installed power cables. The oscilloscope and the spectrum analyzer enable you to see the waveforms and frequencies of the field, which can be very helpful in identifying its source. You can use the same techniques for vibrations and sound levels.

Analysis
You can directly compare the magnetic fields with accelerometer or sound waveforms using the oscilloscope or the chart recorder. Also for example, you can connect the auxiliary input to the video output of an SEM in spot mode to compare magnetic fields with the movement of the electron beam. You can use the SC11 chart recorder to trace intermittent sources of magnetic fields, vibrations or acoustic levels. For example, you can chart the floor displacement or use the narrow band filter to log the magnitude of a known-frequency vibration over a long period. You can use the extended low frequency mode to monitor long term magnetic field fluctuations. This can help you to identify fields due to the movement of such things as steel doors, lifts, trains and trams.

SC11 Hardware

Laptop computer
The laptop computer is optionally supplied by Spicer Consulting with all the software pre-installed. Alternatively you may install the software on your own laptop PC. If desired, Spicer Consulting can install the system on your own computer. The minimum requirement for the computer is a 266 MHz Pentium with 64 MB RAM, 100 MB free hard disc, CD-ROM, 3½in floppy disc drive and PCMCIA slot.

Magnetic Field Sensor
The three axis magnetic field sensor is derived from the Spicer Consulting SC12 range of field canceling systems. The sensor has a magnetic field measurement range of 80 mG pk-pk with a bandwidth of 1 Hz to 5 kHz and a noise limit of 20 uG pk-pk.

Sound Level Meter
The sound level meter supplied is a Techcessories model 33-2050 for general purpose sound measurements. It can measure from 50 to 126 dBA or dBC on its internal meter.

Accelerometer
The accelerometer supplied is a Wilcoxon Research model 731A, with a measurement range of 200 mg's pk-pk and a bandwidth of 0.1 Hz to 500 Hz in this system. The accelerometer is suitable for the measurement of extremely low level vibrations. The accelerometer measures along one independent axis.

The accelerometer can be rotated to measure three orthogonal axes while standing on a horizontal plane.

Flux Gate Magnetometer
The optional flux gate magnetomer is a uMAG-01N from MEDA. It measures one axis magnetic fields from DC to 100 Hz, with a maximum range of ±2000 mG and a meter resolution of 0.01 mG on the most sensitive 20 mG range.

Sensor Calibration

The calibration of the magnetic field sensor is NAMAS traceable. The accelerometer is supplied with a calibration certificate traceable to the National Institute of Standards and Technology, Gaithersburg, MD, USA. Spicer Consulting provides a re-calibration service for the entire system.

Customization

All the virtual instruments can load and save their control settings to named files so that they can be quickly configured for standard measurements. User-defined units may be entered for use with other sensors connected to the auxiliary input.