we began an in-depth look
at the answer to a question that arises numerous times
each year from our customers: “I took a vibration reading
with a portable diagnostic instrument, but it does
not agree with what I am seeing on my Bently Nevada™
monitor. Why?”
Customers often assume that there must be a problem
with the monitor, the diagnostic instrument, or both.
However, as explained in part 1 and as repeated here,
this is rarely the case. Instead, there are some very
straightforward reasons why there are often discrepancies
in vibration readings between two instruments
— particularly peak-to-peak amplitude readings.
In our previous article (ORBIT Volume 25, Number 2,
2005), we defined four stages of a signal as it travels
through a vibration measuring instrument. For convenience,
those stages and the corresponding diagram
are repeated below as Figure 1. |