SKF Multilog On-Line System IMx-M, User Manual, Page: 33 / 313

Protection
Measurement Types
SKF Multilog On-Line System IMx-M 2 - 13
User Manual
Rod length and sensor distance
The rod length and sensor distance are used to translate the measured piston
rod drop, at the sensor position, into the piston drop at the piston center pin
position.
Offset
The Offset is configured in the selected engineering unit (

m or mils) and can
be used to set the measurement to zero. This is done by configuring the offset
to the actual measurement value, obtained either from the
Local Display or
over Modbus .
The offset is subtracted from the measurement at the very end of the
calculations. Because of this the user can compensate the measurement
without the need of performing any tedious calculations to convert the desired
compensation in

m (micrometers) or mils to millivolt.
The configurable offset will affect the measurement in the following way:
If the offset is configured to a positive value the measurement will be
decreased with the value of offset. A negative offset value will increase the
measured value with the same amount.
Offset vs. Zero Level
This offset parameter, which is piston rod drop specific, should not be confused
with the configurable sensor zero level parameter. Although the same result
can be obtained by altering either of them, they are fundamentally different.
While the offset operates at the end of the calculations and with the selected
engineering unit (

m or mils) the zero level operates at the very beginning of
the calculations and in millivolt.
Operating Modes
There are three measurement modes of which two are user configurable through the
IMx-M Manager software.
The configurable modes are Average mode and Triggered mode .
The third mode Runout mode is a measurement mode which will be activated
automatically when specific conditions are met.
Note : In order to avoid running the system in Runout mode
inadvertently which could happen in case of loss of speed/trigger signal,
the user shall enable low speed alarming.
This will ensure that “digital input stuck at low/high” is detected as a
circuit fault.
The alarm setting must be configured for each digital input in use,
including the inputs connected to buffered outputs. See
Alarm Levels
for Speed Type in Digital Channels in IMx-M Manager.