Grundfos CIU 501 User Manual

English (GB)
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2. The slave responds with exception
response 0x01: "Invalid function".
a) The master is trying to use an
unsupported function in CIM/CIU 500.
See section 8. Modbus function code
overview for supported function codes. Note
that reading and writing coils are not
supported, so only register functions and
diagnostics are 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 blocks in
one telegram: this is not possible since
there are unused addresses between
the blocks.
Avoid reading or writing invalid data
addresses. Ensure that a block of registers
starting at address X is addressed as X-1 in
Modbus telegrams, according to the
Modbus standard.
b) The register address offset may have
been changed from default.
Read the holding register at address 00002
"Register Offset" to see if this value is
different from 0. If so, write the value 0 to
this address to make the slave return to the
default used in this functional profile.
4. The slave returns data value 0xFFFF
(65535).
a) The value is unavailable. A data value
of 0xFFFF does not necessarily indicate
an error condition. It means that the
value is unavailable from the booster
system.
See section 9. Modbus register addresses
for available data.
b) The booster system is not configured to
show the value or lacks a sensor to read
the value.
See section 9.8 Pump 1 register block to
9.13 Pump 6 register block for data values
that require a sensor.
5. The slave does not react to control
actions or to writing of settings.
The booster system might be in "Local"
mode, in which case Operating mode,
Control mode and Setpoint cannot be
changed from the bus. Register 00201 bit 8
AccessMode must be "1" (=Remote) for bus
control to be active.
Set the booster system in "Remote mode"
by setting register 00101 bit 0
RemoteAccessReq to "1" (=Remote).
Fault Possible cause Remedy

Grundfos CIU 501 Specifications

General

Brand	Grundfos
Model	CIU 501
Category	Controller
Language	English