ABB REU 610 Technical Reference Manual page 63

1MRS755769
Voltage Relay
Technical Reference Manual
Table 5.1.15.1.-3 Diagnostic counters (Continued)
Name
Slave no response count
Slave NACK response count
Bus character overrun count
The following exception codes may be generated by the Modbus protocol:
Table 5.1.15.1.-4 Possible exception codes
Code Name
01 Illegal function
02 Illegal data address
03 Illegal data value
04 Slave device failure
If an Illegal data value exception response is generated when
attempting to preset multiple registers, the contents of the register to
which an illegal value has been imposed and of the following registers
is not changed. Registers which have already been preset are not
restored.
User-defined registers
Reading of unwanted data in a data block wastes bandwidth and complicates data
interpretation. For optimum efficiency in Modbus communication, data has
therefore been organized into consecutive blocks. In addition, a set of programmable
user-defined registers ( UDR) has been defined in the holding register area.
The first sixteen holding registers, that is, HR1...16, are user-defined registers. The
UDRs can be linked to any holding register, except for HR721...727, using SPA
parameters 504V1...504V16. However, one UDR cannot be linked to another, that
is, linking cannot be nested. Each parameter contains the address of the holding
register to which the UDR is linked.
If a UDR is linked to a non-existent holding register, reading from the register fails
and an Illegal address exception response is sent. Giving the link address
the value 0 disables the UDR. If the master reads from a disabled UDR, the value 0
is returned.
Description
The number of messages addressed to the slave for
which a response (neither a normal response nor an
exception response) has not been sent since its last
restart, clear counters operation or power up.
The number of messages addressed to the slave for
which a NACK response has been sent.
The number of messages addressed to the slave for
which it has not been able to send a response due to a
character overrun since its last restart, clear counters
operation or power up.
Description
The slave does not support the requested function.
The slave does not support the data address or the
number of items in the query is incorrect.
A value contained in the query data field is out of range.
An unrecoverable error has occurred while the slave
was attempting to perform the requested task.
REU 610
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