What are the differences between the SNAP, MATE, LITE and EMDEX II meters?
An EMDEX SNAP meter is designed for simple spot measurements of the magnetic field. The meter displays the measured magnetic field every 0.5 seconds and the user must manually record the measurement values.
The EMDEX MATE meter is designed for simple spot measurements, as well personal dosimetry measurements. Although the meter does not record individual magnetic field values, it does record certain statistical parameters for the measurement period (time-weighted-average, minimum, maximum, standard deviation, etc.). The meter displays the measured magnetic field every 0.5 seconds.
An EMDEX LITE meter is designed to measure and record magnetic field levels at a preset sampling rate. Because it is small and light-weight, the LITE is ideal for personal dosimetry measurements where individual readings need to be recorded. Field versus time plots of the magnetic field can be created to identify different time periods (corresponding to different locations) and associated field strengths.
The EMDEX II meter is designed to be a multi-functional recording magnetic field meter. The meter has a built-in menuing system, allowing the user to set different recording options in the field. Unlike the EMDEX LITE, which can only store one data set, the EMDEX II has the capability of recording up to twenty separate and distinct data sets. A built-in event marker button allows the user to identify (or "mark") certain measurement samples corresponding to certain locations or events. Field versus time plots of the magnetic field can be created to identify different time periods and associated field strengths. The EMDEX II can record electric field strengths (using the E-PROBE electric field sensor accessory) or current strengths (using the AMP-LOGGER current probe accessory). The EMDEX II can also be used in conjunction with a measurement wheel (LINDA wheel accessory) to record field versus distance measurements or map an entire area, and create two-dimensional contour maps or three-dimensional field plots. Using the event marker capability, the EMDEX II can also be used to map areas without using a measurement wheel (using the EMCALC95 software).
Each of the SNAP, MATE, LITE and EMDEX II meters are available in a "standard" version and a "high field" version. What is the difference?
The "standard" field version is designed to measure magnetic fields in the range which are typically encountered in common, everyday locations(such as at home, within a typical office building, at a shopping center, etc.). The "high field" version is designed to measure magnetic fields up into a higher range, which might be found in heavy industrial settings or at electrical facilities, or for characterizing electrical devices, tools, equipment and/or appliances where measurements are desired in very close proximity to the equipment.
The EMDEX II meter is available with two different amounts of RAM memory. What is the difference?
The EMDEX II can collect different types data (magnetic field, electric field or current), at different sample rates (selected by the user), within different parameters (three-axis or resultant only) and different ranges (broadband or harmonic frequencies). Each of these options affects how many samples can be stored in memory. The standard set of RAM memory (156K) is designed to accommodate the typical user and will record, for example, 21.6 hours of broadband resultant magnetic field measurements (at a 1.5 second sample rate). With the larger set of RAM memory (512 K), extended field measurements can be performed for multiple options. For example, 71 hours of broadband & harmonic, magnetic and electric field, resultant data values can be recorded before the memory limit is reached (at a 5 second sample rate). In some cases, the length of the measurement period becomes restricted by the type and life of the 9-volt battery used.
The EMDEX II meter has a built-in menu of operational parameters that can be set by the user. Please describe these parameters.
The EMDEX II has the following user-definable parameters for the "standard" operating program :
Nine preset sample rates - 1.5, 3, 5, 10, 15, 30, 60, 120 or 300 seconds.
Two frequency ranges:
Two operational modes:
Three data storage options:
If the user desires, Enertech can develop a custom operating program for special measurement needs. Please contact Enertech to request a price quotation for custom program development.
The EMDEX II and LITE meters have an on-board computer that can be re-programmed. How is this done?
The EMDEX II has a "UV-EPROM" chip, which stands for Ultra-Violet Electronically Programmable Read Only Memory. This chip contains the internal operating program which controls the EMDEX II meter. When the meter is turned on, the program is transferred from the UV-EPROM to the computer and initiated. If the user wants to change the program, they can download another internal operating program to the computer after it has been turned on. This action will overwrite the transferred program with the new program and the computer will then function according to the new program. However, the original program in the UV-EPROM remains intact. If the EMDEX II is turned off, the current program in the computer is erased. When the meter is turned back on, the program in the UV-EPROM is again transferred to the computer. The only way to change the program in the UV-EPROM is to disassemble the meter, remove the chip, and have a new program "burned" into the chip using an ultra-violet programming device. The EMDEX II can be programmed with a "standard" operating program (magnetic field and current logging parameters), an "electric field" program (electric and magnetic field logging), a "LINDA" operating program (magnetic field versus distance for use with a LINDA measurement wheel), or a "custom" program which the user can develop or Enertech can develop for your specialized needs.
The EMDEX LITE has an "EEPROM" chip, which stands for Erasable Electronically Programmable Read Only Memory. This chip contains the internal operating program which controls the EMDEX LITE meter. When the meter is turned on, the program is initiated from the EEPROM chip. If the user wants to change the program, they can download another internal operating program to the EEPROM chip after the unit has been turned on. This action will erase/overwrite the original EEPROM program with the new program and the new program will remain resident until another operating program is downloaded. If the LITE is turned off, the current operating program remains intact and is initiated whenever the LITE is turned back on. The resident program can be changed as often as the user wishes by simply downloading a new program to the LITE.
The EMDEX II meter comes with the option of having one of three different operating programs burned into the meter. Which one do I want?
The EMDEX II has a burned-in internal operating program which is initiated whenever the meter is turned on. There are different operating programs which are available for different purposes. These programs and their function is listed below :
The standard program, which is the program most individuals normally use, records magnetic field measurements as a function of time. This program is used for stationary location measurements (where the meter is placed at a particular location and left to record the magnetic field for a period of time), personal exposure monitoring (where the meter is worn by an individual to record their exposure), field mapping of a room or area without using a measurement wheel (as explained in the EMCALC95 Manual), or simply for area spot measurements where the data are to be recorded. Two versions of the standard program are currently available :
The LINDA program records magnetic field measurements as a function of distance. This program is used strictly with the LINDA measurement wheel (where the meter is mounted to the measurement wheel and records magnetic field as a function of distance traveled by the wheel). Using the EMDEX II and a LINDA wheel, mappings can be made to create two-dimensional contour maps and three-dimensional magnetic field graphs. You should only request to have this program burned-in to the meter if you intend on primarily performing LINDA wheel measurements on a regular basis (otherwise, it is easier to just download the LINDA program to the meter as occasionally needed).
The Custom program is a very specialized program which the user has either written themselves or asked Enertech to develop for them. The custom program would have certain important measurement parameters defined for a specialized measurement protocol. You should only request to have this program burned-in to the meter for special circumstances or specific measurement protocols.
Can RF (Radio Frequency) sources (i.e. Cell Phones) interfere with an EMDEX II or EMDEX LITE and its measurements?
The EMDEX Lite is shielded for typical ambient RF levels and complies with appropriate immunity standards, however it is not designed nor should it be used for ELF measurements immediately next to intense RF sources. A special RF shielding pouch is available for the EMDEX Lite that provides a major reduction in RF interference.
The EMDEX II is of a different design with more robust rejection of RF (it has more RF immunity), but even the EMDEX II should not be held against an active RF antenna. Measurements of ambient ELF fields should be about 15 cm from a mobile phone when using an EMDEX II or EMDEX Lite in its special RF pouch. The EMDEX Lite with no RF pouch should be at least 1 m or more away from a mobile phone device. An EMDEX Lite (with no RF pouch) can be used to measure personal exposure if it is worn on the opposite hip from a mobile phone (the body shields the RF emissions).