Control Techniques Digitax ST Advanced User's Manual page 145

Parameter Keypad and
Parameter x.00
structure display
11.21 Parameter 0.30 scaling
Bit SP
Coding
Range
0.000 to 9.999
Default 1.000
Update rate Background read
This parameter may be used to scale the value of Pr 0.30 seen via the LED keypad (not via serial comms). Any parameter routed to Pr 0.30 may be
scaled. Scaling is only applied in the status and view modes. If the parameter is edited via the keypad it reverts to its un-scaled value during editing.
11.22 Parameter displayed at power-up
Bit SP
Coding
Range Pr 0.00 to Pr 0.59
Default Pr 0.10
Update rate Background read
This parameter defines which menu 0 parameter is displayed on power-up.
11.23 Serial address
Bit SP
Coding
Range 00 to 247
Default 1
Update rate Background read
Used to define the unique address for the drive for the serial interface. The drive is always a slave.
ANSI
When the ANSI protocol is used the first digit is the group and the second digit is the address within a group. The maximum permitted group number
is 9 and the maximum permitted address within a group is 9. Therefore, Pr 11.23 is limited to 99 in this mode. The value 00 is used to globally address
all slaves on the system, and x0 is used to address all slaves of group x, therefore these addresses should not be set in this parameter.
Modbus RTU
When the Modbus RTU protocol is used addresses between 0 and 247 are permitted. Address 0 is used to globally address all slaves, and so this
address should not be set in this parameter.
11.24 Serial mode
Bit SP
Coding
Range 0 to 2
Default 1
Update rate Background read
This parameter defines the communications protocol used by the 485 comms port on the drive. This parameter can be changed via the drive keypad,
via a Solutions Module or via the comms interface itself. If it is changed via the comms interface, the response to the command uses the original
protocol. The master should wait at least 20ms before sending a new message using the new protocol. (Note: ANSI uses 7 data bits, 1 stop bit and
even parity; Modbus RTU uses 8 data bits, 2 stops bits and no parity.)
Parameter value String
0 AnSI
1 rtU
2 Lcd
ANSIx3.28 protocol
Full details of the CT implementation of ANSIx3.28 are given in Chapter 6 Serial communications protocol on page 210.
Modbus RTU protocol
Full details of the CT implementation of Modbus RTU are given in Chapter 6 Serial communications protocol on page 210.
The protocol provides the following facilities:
• Drive parameter access with basic Modbus RTU
• The protocol supports access to 32 bit floating point parameters
Digitax ST Advanced User Guide
Issue Number: 1
Parameter
description format
FI DE Txt VM DP ND
3
FI DE Txt VM DP ND
2
FI DE Txt VM DP ND
FI DE Txt VM DP ND
1
Comms mode
ANSIx3.28 protocol
Modbus RTU protocol
Modbus RTU protocol, but only with an LCD keypad
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Advanced parameter Serial comms
descriptions protocol
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
Electronic
Performance
nameplate
PS
1
PS
1
PS
1
PS
1
Menu 11
145