Emerson CSI 9420 Reference Manual page 112

Accelerometer EMI and RFI considerations
The armor-jacketed accelerometer cable has one ferrite installed. It is a Steward ferrite
(P/N 28B0672-000), which provides 245 Ω of reactance at 100 MHz.
Figure 6-4:
If your cables require additional immunity after accelerometer installation is complete and
accelerometer cables have been run through a conduit (if applicable), you can place
additional ferrites on the other end of the cable.
Note
The performance of the accelerometer is not maintained beyond a 3-m (10-ft) cable-length unless
you install additional ferrites.
All low-power sensors for use with the CSI 9420 are shipped with additional ferrites if their
cable lengths exceed 3 meters. To ensure compliance with the CE directive, if the cable
length exceeds 3 meters, all standard sensor configurations (1 accelerometer, 1
accelerometer with embedded temperature, or 2 accelerometers) require ferrite
installation at the site.
These ferrites are not installed on the accelerometer cable at the factory because they
must be installed on the transmitter end of the cable, and the cables are typically cut to
length at the site. To maintain compliance with the CE directive, sensors with cables longer
than 3 meters must have 3 additional ferrites installed. You do not need to install the
additional ferrites if the cable length is less than 3 meters.
106
Armor-jacketed accelerometer cable with ferrite installed (as shipped
from the factory)
MHM-97408, Rev 15