Troubleshooting Guide
Component Check
SKF Multilog On-Line System IMx-M
6 - 7
User Manual
4. A protection part diagnostic command "cf" via IMx-M Manager tool would display
circuit fault condition such as:
IOM = 0x8000
IOS0 to IOS7 = 0x0101
RELM, RELS0 to RELS7 = 0x0001
Then, the system resets every couple of minutes, still showing circuit fault condition
such as:
IOM = 0x0000
IOS0 to IOS7 = 0x0101
RELM, RELS0 to RELS7 = 0x0001
5. The only way to solve this problem is to download a configuration again and wait till
system startup before release disarm.
Checking Modbus connection, protection part L1 and L2
1. Check that the physical connections of RS485 cable wire are done correctly:
A, Data + (non-inverting)
B, Data - (inverting)
2. Check that transmission characteristics are defined correctly.
The settings in the protection configuration shall match the settings of the
connected device that shall communicate with the IMx-M (for example, DCS), Baud
rate, stop bits, etc.
3. Check that the Modbus Master-Slave pair address is entered correctly and that the
selected slave device ID (1 - 247) is unique on the RS485 line. If L1 and L2 are
connected to same RS485 line, then they shall have separate slave ID's as well.
4. Check that RS485 termination is done correctly.
If needed, it's possible to connect a termination resistor of 120 Ohm to the device at
the end of the RS485 bus. This could be done by setting RS485 DIP switch 1 (L1)
and 2 (L2) to ON. See chapter
DIP Switches on Protection Module
5. The RS485 LEDs of the front of the PRM shall flash at the same rate as the RS485
communication. If the communication rate is high, a steady light will be shown.
Diagnostic commands mb10 and mb20 may also give some information about the
Modbus communication.
They will report number of received and transmitted messages for L1 (mb10) and L2
(mb20) and if errors are detected. See chapter
