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28
DPF20 Frequency, rate, total or period counter
Instruction Manual
2.3.2
Configuration menu
Speed
(kbps)
57.6
Kbps
...
...
to 600
bps
1 to 247
Address
Configuration
Factory
configuration
Version
Automatic
Decimal point
Move with LE
Manual
Tools
Configure at menu ‘
Configuration
’ (‘rtu’), the address value between
‘1’ and ‘247’ at parameter ‘Address’ (‘Addr’), bus speed in kbps at
parameter ‘Speed’ (‘
bAud
’) and data format at parameter ‘Format
’
(‘
bItS
’).
Special tools are grouped inside the ‘Tools’ (‘TooL’) menu.
• the ‘Decimal point’ (‘dP’) menu is provided for compatibility with
ancient hardware that does not support decimal point retransmis
-
sion. By default, select ‘
Automatic
’ (‘Auto’). If your instrument
does nos transmit the decimal point position, select ‘Manual
’
(‘MAnL’) and fix the position of the decimal point manually.
• at the ‘Factory reset’ (‘FAct’) menu, select ‘yes’ to load the de
-
fault factory configuration for the instrument.
the ‘
Version
’ (‘
VEr
’) menu informs of the current firmware version
installed in the module.
The Modbus RTU protocol defines the following scenarios when a
‘Master’ is sending a frame to a ‘Slave’:
• the ‘Slave’ device receives the frame correctly and replies with the
requested data
• the ‘Slave’ devices detects a CRC error, parity error, or other. and
discards the frame without generating a reply frame. The ‘Master’
will detect a ‘TIMEOUT’ condition due to the absence of reply.
• the ‘Slave’ device receives the frame correctly, but replies with an
‘EXCEPTION_CODE’ as it can not process the function or register re
-
quested.
The ‘EXCEPTION_CODES’ configured in the RTU module are :
2.3.3
Exception codes
Exception
code
Name
Description
0
ILLEGAL_FUNCTION
Requested function is
not supported
1
ILLEGAL_DATA_ADDRESS
Requested register is
not supported
Table 12 - Exception codes
Format
8 bits, no parity, 1 stop
8 bits, even parity, 1 stop
8 bits, odd parity, 1 stop
8 bits, no parity, 2 stop