The GDM-8255A and GDM-8251A portable precision multi-meters engage with 5½, dual-display, 0.012% DCV accuracy and 2w/4w measurement. The VFD display technology provides the excellent observation of contrast and brightness.

GDM-8255A / 8251A carry an extensive list of measurement items - ACV, DCV, ACA, DCA, R, Hz, Continuity beeper, Diode test and Temperature. The dual-display measurement items include ACV + Hz, DCV + dBm, ACV + dBm, DCV + ACV ripple and dBm. Advanced measurement functions, such as Max/Min, Hold, Relative value and Compare, are suitable for multiplicity of applications such as production testing, research and field verification. The USB, RS-232C and 9-pin digital I/O interface are included as standard features, which enable its remote controlling and data capturing for ATE applications.

Fast Measurement Speed / Transfer Rate
GDM-8255A / 8251A offer selectable measurement speed rate under different modes. The speed rates allow users to maximize the measurement efficiency while maintaining sufficient accuracy. At the fast mode, the instrument delivers 60 readings/sec (see table below), adequately meeting today’s speed demand. Besides, the display could be turned off by pressing OUTPUT ON/OFF button at anytime. By doing so, the operation loading could be reduced and entire running speed could be increased since the unit has been remote controlled and not showing the display.

Various Measuring Functions
GDM-8255A / 8251A provide 9 major measuring functions such as DCV/ACV, DCI/ACI, 2w/4w Resistance, Diode, Frequency, Continuity test and Temperature. The 0.012% DC voltage accuracy provides user the best measuring precision at the DC voltage applications. In addition, there are several advanced measuring functions such as Max, Min, dB, dBm, REL/REL#, Hold, Compare and Math functions to enhance the serviceability of measuring results.

2/ 4 Wire Resistance Measurement GDM-8255A / 8251A offer two methods for resistance measurement.
2-wire resistance measurement is the most common and simplest connection method, typically used in the impedance greater than 1k.
4-wire resistance measurement is required for accurate low impedance measurement. Once the 4-wire measurement is applied, the test lead resistance and contact resistance will be reduced automatically.

Combinational Dual Measurement Function
GDM-8255A / 8251A offer varieties of dual display combinations with main measurement function which allows GDM-8255A / 8251A to measure two properties of input signals. The dual measuring function will save customers measurement time when dealing with applications requiring multiple parameters simultaneously.

Multiple Standard Interfaces GDM-8255A / 8251A provide the standard multiple interfaces for PC connection: RS232C and USB device port. Unlike the common RS232 transfer speed, the GDM-8255A / 8251A even raises the baud rate up to 115200 which would be 12 times faster. It would make the command or data flow faster and smoother. Besides, it is not necessary to expend the fabrication in order to communicate with a PC. It would certainly reduce the user cost. In addition, the digital I/O terminal outputs the result of comparison measurements to control external devices for ATE applications. By providing an independent VCC for the terminal, the digital I/O outputs can also be used as power source for TTL or CMOS logics.

Free PC Software – Remote Control & Data Capture
For a convenient remote control and a long data capture, the GDM-8255A / 8251A accompanies free software, DMM-Viewer. This software allows users to remotely control the GDM-8255A / 8251A without entering extra commands. Besides, the software interface and even the measurement method resemble those of GDM-8255A / 8251A front panel, thus guaranteeing safe operation and shortened training and program development time.

For data capturing through a PC, the software allows users to observe measuring result before saving it as a file for further study. In addition, the saved data could be reloaded for converting into a graph. With the DMM-Viewer PC software, the user operation of GDM-8255A / 8251A can be much more effective.

Buffer Store / Recall Function GDM-8255A / 8251A provide an internal buffer for storing up to 10,000 counts of measuring data, and it allows users to recall the test records for observation or analyzing the maximum, minimum, or average values after the internal processing is completed.