Emerson E300 Series Design Manual page 408

Safety Product Mechanical
information information installation
The core drive always uses the Modbus rtu protocol and is always a slave. Serial Mode (M02) defines the data format used by the serial comms
interface. The bits in the value of Serial Mode (M02) define the data format as follows. Bit 3 is always 0 in the core product as 8 data bits are required
for Modbus rtu.
Bits 3
Number of data bits
Format 0 = 8 bits
1 = 7 bits
Bit 2 selects either standard or modified register mode. The menu and parameter numbers are derived for each mode as given in the table below.
Standard mode is compatible with Unidrive SP. Modified mode is provided to allow register numbers up to 255 to be addressed. If any menus with
numbers above 63 should contain more than 99 parameters, then these parameters cannot be accessed via Modbus rtu.
Register mode
Standard
Modified
Changing the parameters does not immediately change the serial communications settings. See Reset Serial Communications (M06) for more
details.
M03 Serial Baud Rate
Mode Open-Loop, RFC-A, RFC-S
Minimum 0
Default 6
Type 8 Bit User Save
Display Format Standard
Coding RW, Txt
Value
0
1
2
3
4
5
6
7
8
9
10
Serial Baud Rate (M03) defines the baud rate used by the serial comms interface.
Changing the parameters does not immediately change the serial communications settings. See Reset Serial Communications (M06) for more
details.
M04 Minimum Comms Transmit Delay
Mode Open-Loop, RFC-A, RFC-S
Minimum 0
Default 2
Type 8 Bit User Save
Display Format Standard
Coding RW, BU
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 1ms after the message has been received from the host allowing 1ms for the
host to change from transmit to receive mode. This initial delay can be extended using Minimum Comms Transmit Delay (M04) if required.
408
Electrical Getting
User Menu A Commissioning
installation started
2
Register mode
0 = Standard
1 = Modified
Register address
(mm x 100) + ppp - 1 where mm ≤ 162 and ppp ≤ 99
(mm x 256) + ppp - 1 where mm ≤ 63 and ppp ≤ 255
Text
300
600
1200
2400
4800
9600
19200
38400
57600
76800
115200
Advanced
Diagnostics Optimization CT MODBUS RTU Technical Data
Parameters
1 and 0
Stop bits and Parity
0 = 2 stop bits, no parity
1 = 1 stop bit, no parity
2 = 1 stop bit, even parity
3 = 1 stop bit, odd parity
Maximum
Units
Update Rate
Decimal Places
Maximum
Units
Update Rate
Decimal Places
10
Read on serial communications reset
0
250
ms
Read on serial communications reset
0
E300 Design Guide
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