INSTALLATION AND OPERATING INSTRUCTIONS
Troubleshooting
46 (66)
SKF Multilog On-line System IMx-16Plus
User Manual
Revision Letter A
NO: A relay fault is indicated.
YES: The IMx-16Plus and relay sub-system seems as expected. Check the
downstream system components (that the correct relay output contacts are
being used, the power supply on the relay contact side, the ‘detecting’ device
etc.).
4. Measure the DC voltage at the relay coil terminals, using a digital voltmeter.
Is it approximately 24 V DC?
YES: Check again that the correct relay output is being tested and
that the configuration is correct. Check also that this relay is wired to
the correct IMx-16Plus, relay driver output.
If so, the test suggests a fault in the IMx device, contact TSG for
further advice.
NO: The IMx-16Plus relay driver output seems as expected.
Check the downstream system components (that the correct relay
output contacts are being used, the power supply on the relay contact
side, the ‘detecting’ device etc.).
2.9.5 RS485 Modbus RTU communications
Communications can be affected either by physical (typically wiring) issues for the
RS485 bus and/or configuration issues related to the protocol (Modbus RTU).
Physically these are, differential, 2-wire interfaces with the two wires marked as A
and B. Whilst it is normal to connect ‘A to A’ and ‘B to B’ it is not
unheard of, to have
inconsistent marki
ng on different manufacturer’s equipment.
So, when interfacing to
‘new’ equipment and experiencing problems it is worthwhile to test with the
connections swapped, as no damage will be done by operating with swapped RS485
connections. Bear in mind if there are multiple issues (say a configuration problem
and an incorrect connection), all issues will have to be solved before a
communications test will be successful. Pay attention also to bus termination and
grounding, as described in section
When using the interface, the connection will be between a single master and one (or
sometimes more) slave devices, each slave must have a unique address (in the
range 1 to 247). The master device initiates all communications the slave device only
ever responds, if asked to send a reply. Incorrect addressing (a mismatch between
the address at which the master understands the slave resides and that actual
address) will result in unanswered messages.