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14. Fault finding
14.1 CIU 202
You can detect faults in a CIU 202 by observing the status of the
two communication LEDs. See the table below and section
.
14.1.1 LED status
Fault (LED status)
Possible cause
Remedy
1. LED1 and LED2 remain off when the
power supply is connected.
a) CIM 200 is fitted incorrectly in CIU 202. Ensure that CIM 200 is fitted correctly.
b) CIU 202 is defective.
Replace CIU 202.
2. LED2 for internal communication is
flashing red.
a) No internal communication between
CIM 200 and CIU 202.
Ensure that CIM 200 is fitted correctly in
CIU 202.
3. The LED2 for internal communication is
permanently red.
a) CIM 200 does not support the in which it
is installed.
Contact the nearest Grundfos company.
4. The Modbus LED1 is permanently red.
a) Fault in the CIM 200 Modbus
configuration.
• Check the transmission speed, switches
SW4 and SW5. If the switches are set to
"software-defined", an invalid value may
have been set via Modbus. Try one of the
preselected transmission speeds, for
example 19200 bits/s.
• Check that the Modbus address
(switches SW6 and SW7) has a valid
value [1-247].
5. The Modbus LED1 is flashing red.
a) Fault in the Modbus communication
(fault in parity or cyclic redundancy
check).
• Check the transmission speed, switches
SW4 and SW5.
See section
• Check the parity settings, switch SW3.
.
• Check the cable connection between CIM
200 and the Modbus network.
• Check the termination resistor settings,
switches SW1 and SW2.
See section
