For those who are willing to spend the money on a top-end multimeter with plans on more advanced robot building, they may choose to purchase a multimeter with features that are not required for the average robot builder. In two previous articles I discussed the required and recommended features of multimeters for robot building. I will be concluding my discussion on multimeter features with this article on the optional features of multimeters. These optional features optimize the process of testing different parts for their electrical denominations and make robot building a more involved and enjoyable activity:
Inductance gives an indication as to the extent of opposition to the change in flow of electricity, and is measured in henries. This is a rare feature and is only found in a few multimeters.
RS-232 Data Interface
The Recommended Standard 232 allows for communication of data between a multimeter and a computer or other device. Such a data interface is crucial when producing test logs. Despite its communicative abilities, multimeters with data interface do not replace oscilloscopes, since multimeters only update data a few times every second. If you plan on purchasing a multimeter with an RS-232 data interface, make sure you purchase the software that must be installed in order for you to transfer data from the multimeter to your computer.
The scope mode takes measured data values and graphs them over a certain time scale. When analyzing the quality of timing signals and data pulses, the scope mode becomes crucial. However, the limited scope mode of a multimeter does not compete with a more powerful oscilloscope, but are still useful for the average robot builder. Be careful when deciding whether or not to purchase a multimeter with a scope, since the scope mode typically results in a significant increase in price.
The temperature mode gives an indication as to how hot or cold something is, and is measured in degrees Celsius or degrees Fahrenheit. This feature is helpful when determining whether a part is too hot, or whether a part is functioning outside its optimal temperature range.
The sound mode gives an indication as to how loud or quiet something is, and is measured in decibels. This feature can be useful when performing volume tests on parts such as speakers and motors.
When a part is being tested by a multimeter and there is a change in a measurement value, the multimeter does not record every change. Rather, the multimeter takes an average of the values over a small period of time and displays this average a few times every second. All multimeters display a numerical value, but some display the value as a bar graph as well.
The relative mode calculates the difference between the last measurement and the current measurement. This mode is useful when testing the differences in electrical denominations of similar parts.