UCM Calibration
Page 36
FlexPI Product Guide
Step 1 - Setting the Filter Response
The Filter Response setting depends primarily on the type of surface on which the sensor cable is
mounted:
•
If the sensor cable is installed on a surface that can have a dampening effect on vibrations
(e.g., wood, drywall, plasterboard, cement, brick, stone, masonry, etc.) select the low band
filter response (SW5-1 ON - 100 to 300 Hz).
•
If the sensor cable is mounted on a stock cage, or sheet metal, or a steel structure that
conducts vibrations quite well select the high band filter response (S5-1 OFF - 300 to 900 Hz).
Step 2 - Calibrating the FlexPI Gain/Threshold
The Gain/Threshold is used to amplify the input signal from the sensor cable before it is
processed. FlexPI has four Gain/Threshold Settings ranging from 1 (lowest) to 4 (highest). Refer
to
for a flow chart of the Gain/Threshold calibration procedure.
1.
Begin by setting the switches as indicated in
2.
With S4-1 ON and all other S4 switches OFF (Gain = 2). View the bar graph and verify that
either, only the first red LED is illuminated, or that all LEDs are OFF.
3.
Test the signal response with a series of impacts on the protected surface, along the length of
the sensor cable. Look for a response that is above the Threshold (6th LED is illuminated) but
below the top of the bar graph (10th LED is OFF).
4.
If the signal response does not illuminate the green LED, increase the Gain setting one level
and repeat the test.
OR
If the signal response always reaches the top of the bar graph, decrease the Gain setting one
level and repeat the test.
5.
When the impacts consistently result in a response that is above the Threshold (green LED
ON), and does not always reach the top of the Bar graph, the Gain/Threshold setting is correct
for the installation.
Note
In most cases, the frequency created by an impact does not vary
significantly from that of a sustained attack.
Note
If either the protected surface or any nearby equipment resonates at
a frequency included in the processor’s Filter Response bands, select
the band that excludes the resonant frequency.
Note
Although the Gain/Threshold Setting amplifies the received signal it
also amplifies the environmental background noise. Use care when
adjusting the Gain/Threshold.
Figure 27: Recommended switch settings
2.0 SEC
S1 CLIMB
1
3 4
2
S2 TIME WINDOW
32 SEC
1
3 4
2
4 IMPACTS
S3 CUT
1
3 4
2
SW5-1
HIGH BAND FILTER RESPONSE 300 Hz TO 900 Hz
LOW BAND FILTER RESPONSE 100 Hz TO 300 Hz
= SWITCH OFF
= SWITCH ON
S4 GAIN/THRESHOLD
1
3 4
2
S5 MISC
1
3 4
2
set S5-1 according to the type of mounting surface
*
*
