SKF Multilog On-Line System IMx-M, User Manual

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Hardware
Installation
4 - 8 SKF Multilog On-Line System IMx-M
User Manual
Important - If an IMx-M rack is used with only one ground (PE), then a GND
jumper (PE connected to IGND) must always be in place (as shown in the figure
above). Otherwise, If the IMx-M rack is used with separate grounding (PE and
IGND), then GND connector jumper should be removed and instrument ground is
connected to IGND pin.
Important - SKF USB isolator cables shall always be used when connecting to
IMx-M USB ports.
Important - Equipment connected to buffered outputs must be isolated from
the protective earth.
Important - IGND signals should be connected to protective earth/ground at
one point only.
Important - An IMx-M rack must be connected to protective earth since surge
suppressors are connected between network terminals and protective earth.
Signal Isolation
Galvanic isolated parts (Maximum allowed voltage difference relative to protective earth
is 40 V):

4
–
20 mA output block (not individually isolated)

Ethernet ports (individually isolated)

Protection redundant Modbus RS485 L1, L2 (individually isolated)

All relays are potential free relays (individually galvanic isolated).

Digital inputs D1-D8 are optically isolated inputs (individually isolated)

Disarm input
( Note : shared ground terminal with RS485, L2)
Electrical isolated parts, differential inputs:

Analog inputs are differential inputs and support common mode up to ± 25 V
relative to IGND.
Parts relative to Instrument Ground IGND (should be used with care to prevent ground
loops, see also
Signal Grounding :

Buffered outputs (connect only to isolated /differential inputs).

USB ports are relative to instrument ground.