Baud Rate; Minimum Comms Transmit Delay - Emerson Mentor MP Advanced User's Manual

Parameter
Menu 11
structure
The protocol provides the following facilities:
• Drive parameter access with basic Modbus RTU
• Drive parameter access via CMP extensions
• Solutions Module internal parameter access via CMP extensions
• Access via a Solutions Module onto a network via CMP extensions (see specific Solutions Module specifications for details)
• Drive parameter database upload via CMP extensions
• Drive Onboard Application Lite Ladder program upload/download via CMP extensions
• The protocol supports access to 32 bit floating point parameters
The following product specific limitations apply:
• Maximum slave response time when accessing the drive is 100 ms
• Maximum slave response time when accessing Solutions Module internal parameters or via a Solutions Module to a network may be longer than
100 ms (see specific Solutions Module specifications for details)
• Maximum number of 16 bit registers that can be written to, or read from, the drive itself is limited to 16
• Maximum number of 16 bit registers that can be written to, or read from, a Solutions Module or via a Solutions Module - see specific Solutions
Module specification
• The communications buffer can hold a maximum of 128bytes
Modbus RTU is also supported via the keypad synchronous serial interface. This is covered in a separate specification related to the keypad port.
Modbus RTU protocol, but with LCD keypad only
When this mode is selected it is only possible to read or write parameters in menu 99 within the drive and only using Modbus rtu (excluding FC40).
Also Pr 99.29 is set to one by the drive. If Pr 99.29 is set to zero full communications is enabled for 5 seconds, after which Pr 99.29 is reset to one by
the drive. This feature is provided so that users can restrict the use of the 485 comms port to the LCD keypad only. When this mode is selected
access to the restricted menu 99 is only applied to the RS485 port and not the keypad port.
11.25

Baud rate

{Si01, 0.66}
Bit SP
Coding
Range 0 to 9
Default 6
Update rate Background read
Used in all comms modes to define the baud rate.
Parameter value String/baud rate
0
1
2
3
4
5
6 19200
7 38400
8* 57600
9* 115200
*Modbus RTU only
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 baud rate. The master should wait at least 20 ms before sending a new message using the
new baud rate.
11.26

Minimum comms transmit delay

Bit SP
Coding
Range 0 to 250 ms
Default 2
Update rate Background read
There will always be a finite delay between the end of a message from the host (master) and the time at which the host is ready to receive the
response from the drive (slave). The drive does not respond until at least 1 ms after the message has been received from the host allowing 1 ms for
the host to change from transmit to receive mode. This initial delay can be extended using Pr 11.26 if required for both ANSI and Modbus RTU
protocols.
146
Keypad and
FI DE TE VM DP ND
1
300
600
1200
2400
4800
9600
FI DE TE VM DP ND
www.onxcontrol.com
Advanced parameter
format
Parameter description
RA NC NV PT US RW BU
1 1
RA NC NV PT US RW BU
1 1
Serial comms
protocol
descriptions
PS
1
PS
1
Mentor MP Advanced User Guide
Performance
Issue Number: 4