Serial Port - Modbus RTU configuration page

Use the Modbus RTU configuration page to do the following actions:
The displayed configuration settings vary with the
Micro800
 controller selection.
Modbus RTU configuration settings
Setting
Description
Common Settings
Diagnose
Opens the communication diagnostics view.
Diagnose
 is available when the controller is online and
CIP Serial
 or
Modbus RTU
 is selected as the driver.
Baud rate
Lists the baud rate in bits per second. Options are:
  • 1200
  • 2400
  • 4800
  • 9600
  • 19200
  • 38400
The default baud rate is 19200.
Parity
Lists the parity bit usage in the communication packets. Options are:
  • None
  • Odd
  • Even
The default value is None.
Modbus role
Specifies the role of the Modbus port. Options are as follows:
  • Master
  • Slave
  • Auto
The default option is
Master
.
Unit address
Specifies the Unit ID if configured as a Modbus server (slave).
The option is not available when
Modbus role
 is set as
Master
.
When you select
Slave
 or
Auto
 for
Modbus role
, the unit address is from 1 through 247. The default value is
1
.
For instance, in a scenario where the controller is set up as a Modbus RTU slave that is connected to a
PanelView™
Component (PVC), the PVC is the Modbus master and uses the address of 0.
Protocol Control
Media
Specifies the supported media types. Available options for L50E and L70E controllers are:
  • RS232
  • RS485
Control line
Specifies the type of handshake that is used for communication.
  • Select
    RTS/CTS
     if both the master and slave are using half-duplex modems.
  • Select
    No Handshake
     for direct point-to-point communication without a modem.
Data bits
Specifies the number of data bits per character. The value is 8 and is read-only.
Stop bits
Specifies the number of stop bits per character. Options include
1
 and
2
. 1 is the default option.
Response timer
Specifies a Modbus master's minimum waiting time for a response from the Modbus slave before a new transmission can begin.
The value is from 0 through 4,294,967,295. The default value is 200.
In a scenario where the
Micro800
 controller serves as a master of the Modbus RTU slave, to send a complete response, the value must be restricted within the required time from the slave.
Broadcast pause
Specifies the amount of time to delay after the data broadcast. The value is from 0 through 4,294,967,295. The default value is 200.
Inter-frame (delay/timeout)
Specifies the amount of time to delay after a transmission request. The value is from 0 through 4,294,967,295. The default value is 0.
RTS pre-delay
Specifies the amount of time to delay before requesting a transmission. The option is available when
Media
 is set to
RTS32
 and
Control line
 is set to
RTS/CTS
.
The value is from 0 through 4,294,967,295. The default value is 0.
The option is available when
Media
 is set to
RS232
 and
Control line
 is set to
RTS/CTS
.
RTS post-delay
Specifies the amount of time to delay after requesting a transmission. The option is available when
Media
 is set to
RTS32
 and
Control line
 is set to
RTS/CTS
.
The value is from 0 through 4,294,967,295. The default value is 0.
The option is available when
Media
 is set to
RS232
 and
Control line
 is set to
RTS/CTS
.
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