The Setting ‘COMx - Modbus’¶
Note
At AC500-eCo CPUs PM55x and PM56x, the parameter Parity cannot be configures as Mark and/or Space.
For the protocol setting ‘MODBUS’, the following window is displayed:
The following settings are possible:
| 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 |
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| 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 |
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| 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 |
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| XON/XOFF | Software handshake -> Not yet implemented |
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| 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 |
| Master | Master | ||
| Slave | Slave | ||
| 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 |
The selection “COMx - MODBUS” sets the serial interface x to the Modbus protocol Communication \ with Modbus® RTU and Modbus® TCP/IP.
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.