Hardware
Installation
SKF Multilog On-Line System IMx-M
4 - 7
User Manual
Appropriate, clearly marked, all-pole local isolators should be provided to enable
the rack to be de-energized for maintenance.
It is required that the IMx-M rack must be connected to protective ground/earth (PE).
Refer to
for attaching power cable to the mains power/power grid.
Important - The cross section area of the PE wire must be equal or greater
than the cross section area of the power wires. The PE wire should be color labeled
green/yellow. However, in some countries, other cable requirements may apply.
Signal Grounding
Figure 4 - 4.
Instrument Ground Jumper - Instrument Ground (IGND) Connected to Protective Ground (PE).
If instrumentation ground is available, connect the instrumentation ground to IGND,
and connect the protective ground to PE. Otherwise, connect a cable as shown in
the figure, above.
Analog input's shield and digital input's shield are connected to IGND and should
always be separated from Protective ground to eliminate noise/interference.
Buffered outputs are relative to instrument ground. If system is set up for separate
grounding (PE and IGND) then user must ensure that buffered outputs are
connected to IGND systems or systems with isolated/differential inputs.
USB galvanic isolator provided by SKF should always be used to prevent ground
loops.
If an IMx-M rack is used with separate grounding (PE and IGND), then GND
connector jumper (as shown in the figure above) should be removed and
instrument ground is connected to IGND pin.
Important - Signal grounding procedure must be handled with special care to
avoid ground loops. Be sure to read this "Signal Grounding" chapter thoroughly and
understand it.
Important - The sensor shield and/or sensor inner shield should be connected
either to the sensor or to the IMx-M rack depending on the cable and the sensor
type, but NOT to both.
