English (GB)
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14.2.2 CIU 262 Modbus connection communication faults
Fault
Possible cause
Remedy
1. The slave does not respond to
telegrams.
a) Configuration or installation error.
• Ensure that CIU 262 has contact with the
cellular network. LED1 should be pulsing
yellow.
If the LED1 signal is incorrect, see
section
for correct installation of
the CIM 260.
• Ensure that the correct slave address is
used in the Modbus master poll.
See register 00003
SoftwareDefinedModbusAddress (factory
value is 00231).
b) The slave may be in listen-only mode.
Either send a restart communications
diagnostics command, or restart the
product manually.
c) If the holding register of address 00001
"SlaveMinimumReplyDelay" is set too
high, the master may time out before
receiving the response from the slave.
Increase the reply delay in the master, or
reduce the "SlaveMinimumReplyDelay" in
order to communicate.
2. The slave responds with exception
response 0x01: "Invalid function".
a) The master is trying to use an
unsupported function in CIU 262.
for supported function codes.
Note that reading and writing coils is not
supported, so only register functions and
diagnostics will be valid.
3. The slave responds with exception
response 0x02: "Invalid data address".
a) The master is trying to read or write an
invalid data address. If a master tries to
read register addresses that are not listed
in the tables, the slave responds with this
exception response. Some masters may
automatically try to read large blocks in
one telegram, which will cause problems if
some of the registers in the block are not
supported. An example would be reading
the CIM configuration and CIM status
register blocks in one telegram. This is not
possible since there are unused
addresses among the blocks.
Avoid reading or writing invalid data
addresses.
Ensure that register X is addressed as X - 1
in Modbus telegrams, according to the
Modbus standard.
4. The slave returns data value 0xFFFF
(65535).
a) The availability of data will in some cases
depend on a configuration or the actual
conditions of the system. For example
trying to request data from a pump which
is not present will return "data not
available", 0xFFFF.
See section
for
available data.
b) With its present configuration or operating
mode, the Grundfos product is unable to
supply the requested data.
for
data values that require a sensor.
5. The slave does not react to control
actions or to writing of settings.
a) CIU 262 is SCADA PIN-code-protected
(GeneralStatus register 00029, bit 0: 1),
and an incorrect PIN code has been
written.
Write access requires a correct PIN code
(ScadaPinCode, register 00011). Writing the
correct PIN code value triggers the write
access control, and write access is open,
which can be verified with GeneralStatus,
register 00029, bit 1 = 1.
