Setting COMx - MODBUS

Right-click COMx_Online_Access -> Add object
and select COMx_MODBUS from the list.

The following parameters are available:

Parameter Default value Value Meaning
Enable login Disabled Disabled There is no check with regard to the Control Builder login telegram.
Enabled

Telegrams received are checked with regard to the Control Builder login sequence. If the sequence is detected, the protocol setting is changed to ‘Online access’.

-> available as of firmware V1.2.0

RTS control None None No RTS control (not for PM55x and PM56x CPUs)
Telegram

RTS control for telegram activated

-> available as of firmware V1.2.0

TLS 0 0…65535

Carrier lead time in [ms] or characters (TLS > CDLY)

-> available as of firmware V1.2.0

CDLY 0 0…65535

Carrier delay time in [ms] or characters (CDLY <= TLS)

-> available as of firmware V1.2.0

Telegram ending value 3 0…65535 Number of characters for character timeout
Handshake None None No flow control
RTS/CTS

Hardware handshake

-> available as of firmware V1.2.0

XON/XOFF

Software handshake

-> Not implemented

Baudrate 19200

300

1200

4800

9600

14400

19200

38400

57600

115200

125000

187500

Character length in bits/s
Parity Even None No parity
Odd Odd parity
Even Even parity
Mark Parity bit := TRUE
Space Parity bit := FALSE
Data bits 8 5, 6, 7, 8 Number of data bits, 5 to 8
Stop bits 1 1, 2 Number of stop bits, 1 or 2
Operation mode None None None
Server Server
Client Client
Address 0 0…255 Address for MODBUS slave
Disable write to %MB0.x from 0 0…65535 Disable write access for segment 0 starting at %MB0.x
Disable write to %MB0.x to 0 0…65535 Disable write access for segment 0 up to %MB0.x
Disable read to %MB0.x from 0 0…65535 Disable read access for segment 0 starting at %MB0.x
Disable read to %MB0.x to 0 0…65535 Disable read access for segment 0 up to %MB0.x
Disable write to %MB1.x from 0 0…65535 Disable write access for segment 1 starting at %MB1.x
Disable write to %MB1.x to 0 0…65535 Disable write access for segment 1 up to %MB1.x
Disable read to %MB1.x from 0 0…65535 Disable read access for segment 1 starting at %MB1.x
Disable read to %MB1.x to 0 0…65535 Disable read access for segment 1 up to %MB1.x

Note

At AC500-eCo Processor Modules the parameter Parity cannot be configured as mark and/or space.

For MODBUS slave operation, an area without read and/or write access can be set in the segments %M0.x and %M1.x. reading/writing is disabled beginning at the set address and is valid up to the set end address (inclusive).

Note

The parameter Data bits always has to be set to 8 for MODBUS.