I put the max
trim to the maximum. How could I know if my volmeter is
RMS?
Please take the time to read the referenced website below at the bottom.
If you don't have the paperwork on the
meter still in your possession, try looking your exact model up on-line. The info on True
RMS/ not True
RMS should be there. If not I'd be suspecting it is NOT True
RMS. My guess is the
MSRP for true
RMS meters is around $100 or more, but prices may be lower. So if it was inexpensive it may not be true
RMS. Make sure it is a "True
RMS"
rating.
The following may not apply to you, but just in case:
Also, I feel,
Category rating is important if your using the
meter to check High
Voltage lines. I'm not sure if 120V is as crucial as 480V and up for protection of the meters from high
voltage transients. Others here will know...
Excerpt from Broadcast Engineering website:
Rating a
meter by both
category and
voltage can be confusing, so here’s an explanation. If you ever work on
power circuits then you need at least a CAT II or CAT III rated
meter. Use only a
meter with the proper
category and an associated
voltage rating, such as CAT III-600V or CAT III-1000V, marked on the front of the
meter.
Old meters were rated with steady-state
voltage withstand levels. So, in that sense, a 1000V-rated
meter would be safer than a 750V-rated
meter. But in today’s
rating system that thinking only applies to meters in the same
category. This means that a CAT III-1000V
meter has better protection than a CAT III-600V
meter. However, a CAT II-1000V
meter is NOT “safer” than a CAT III-600V
meter. Here’s why.
Under UL specifications, a CAT III-600V
meter must pass a test against a transient with much more energy than the CAT II-1000V
meter. A CAT III-600V will be tested with a transient, having the same peak
voltage, but one that has one-sixth the test source
impedance and therefore six times the
current of the CAT II-1000V
meter! Be sure you understand this key difference when selecting voltmeters.
A final
meter purchase caveat. In addition to selecting voltmeters by
category and
voltage, look for certification by an independent testing lab, such as UL or
CSA (Canadian Standards Association). Such certified meters have actually passed the mandated tests. Don’t
settle for a
meter that just says “designed to meet” or “conforms to
IEC 61010.” Those statements are no substitute for independent testing. The adage, “It looks good on paper” is no substitute for real-world testing. Don’t let yourself become that one statistic where the
meter “test” failed.
From Broadcast Engineering website:
How safe is your voltmeter? | Brad on Broadcast