HYDAC HMG 3000 - Manual (Page 36)

HMG 3000 Page 36
Edition 11/2007 - V02 R01-S02 Stock no.: 669712
Sampling rate
This item enables you to set the rate at
which the HMG reads a measured value
from the sensors and stores it in the internal
memory. A measurement curve may
comprise up to 500,000 measured values.
Selecting 1 ms, for example, means that
1000 measured values per second are taken
and stored for each connected measurement
channel.
Use the arrow keys (
↑ ) and ( ↓ ) to scroll
through the various settings for the sampling
rate. At the bottom of the display you see
information on the resulting recorded data
(number of data records and memory
usage). If you select an invalid setting,
meaning that the sampling rate selected by
you would exceed the 500,000 maximum,
you are shown a message in lieu of the
recorded data describing the invalid setting
made by you.
The sampling rate selected depends
primarily on the measurement task at hand.
A sampling rate of 1 s is probably sufficient
for monitoring the temperature in a hydraulic
tank, as temperature changes generally
progress slowly. If, however, you want to
track extremely rapid system-induced
pressure surges, whose occurrence
frequency is generally in the millisecond
range, you have to work with a sampling rate
of 1 ms or less.
HYDAC HSI pressure transmitters with
automatic sensor detection are capable of
tracking rectangular pressure pulses
(theoretically occurring in a time of 0 s)
within 0.5 ms apart. This means that simply
setting a sampling rate of 0.1 ms is not
sufficient to capture pressure surges
occurring faster than 0.5 ms apart. A suitable
dynamic pressure transmitter also has to be
used.