Modbus Rtu / User Serial Mode; Serial Comms Baud Rate; Silent Period Extension; Drive Configuration - Emerson 2202 Advanced User's Manual

Parameter
Menu 11 Introduction
x.00
Address 0 is used to globally address all slaves, and so this address should not be set in this parameter.
The communications port on the Commander SK will support Modbus RTU protocol only. Full details of the CT implementation of Modbus RTU are
given in "CT MODBUS RTU specification".
The protocol provides the following facilities:
• Drive parameter access with basic Modbus RTU
• Drive parameter database upload via CMP extensions
The following product specific limitations apply:
• Maximum slave response time when accessing the drive is 100ms
• Maximum number of 16 bit registers that can be written to, or read from, the drive itself is limited to 16
• The communications buffer can hold a maximum of 128 bytes
11.24

Modbus RTU / user serial mode

Bit SP
Coding
Range 0 to 3
Default 1
Update rate Background
Modes 0, 1 and 4 are for Modbus slave mode. Modes 2 and 3 allow a drive user program to control the comms.
0: mode 0 8 data bits and 1 stop bit with no parity (Commander SE backward compatibility)
1: mode 1 8 data bits and 2 stop bits with no parity
2: mode 2 7 data bits and 1 stop bit with even parity
3: mode 3 8 data bits and 2 stop bits with no parity
4: mode 4 8 data bits and 1 stop bit with even parity
11.25

Serial comms baud rate {43}

Bit SP
Coding
Range 2.4(0), 4.8(1), 9.6(2), 19.2(3), 38.4(4),
Default 19.2(3)
Update rate Background
This parameter is used to select the comms port baud rate in kilo baud.
11.26

Silent period extension

Bit SP
Coding
Range 0 to 250 ms
Default 2
Update rate Background
Modbus RTU uses a silent period detection system to detect the end of a message. This silent period is normally the length of time for 3.5 characters
at the present baud rate, but for systems that cannot turn the communications buffers around fast enough this time can be extended to the time
programmed in Pr 11.26.
11.27

Drive configuration {05}

Bit SP
Coding
Range AI.AV(0), AV.Pr(1), AI.Pr(2), Pr(3), PAd(4), E.Pot(5), tor(6), Pid(7), HVAC(8)
Default Eur: AI.AV(0), USA: PAd(4)
Update rate Actioned on exit of edit mode or drive reset.
This parameter is used to automatically set up the user programmable area in the level 3 parameter set according to the required drive configuration.
Other default parameters may also be changed automatically by the drive configuration. See Table 10-23 for drive configuration parameter changes.
A change to Pr 11.27 is set on the exit of parameter edit mode or on a drive reset. The drive must be disabled, stopped or tripped for a change to take
place. If Pr 11.27 is changed while the drive is running, the parameter will return to its pre-altered value. Following a drive configuration change, the
parameters are automatically stored in EEPROM.
In all of the following settings, the status relay is set up as a drive ok relay.
T5
OK Fault
T6
140
Parameter Keypad and
description format display
FI DE Txt VM DP ND
FI DE Txt VM DP ND
1
FI DE Txt VM DP ND
FI DE Txt VM DP ND
1
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Serial CT Modbus PLC Ladder
communications RTU programming
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1 1
Advanced parameter
CTSoft Menu 0
PS
1
PS
1
PS
1
PS
1
Commander SK Advanced User Guide
Issue Number: 9
descriptions