Setting COMx - Online Access¶
By default, the serial interfaces are set to ‘Online access’. That means the access is done with help of Automation_Builder.
If the default mode is set to another value, the interface protocol is directly set in the PLC configuration. No block (such as MODINIT, COMINIT) is required.
The serial interface settings can be read in online mode using the PLC browser commands “com settings” and “com protocols”. Chapter AC500-specific PLC browser commands contains a description of these commands PLC Browser Commands: AC500-Specific PLC Browser Commands
If COMx - Online Access is selected, the interface parameters are set to the following fixed values:
- Baudrate=19200 Baud
- Stop bit=1, Parity=none
- Data bits=8
Note
The parameter RTS control is set to telegram. This also allows programming via RS-485 (for example using an according converter). For AC500 PM55x and PM56x CPUs, the parameter RTS control is set to telegram by default. This allows programming via RS-485.
Double-click COMx_Online_Access to open the COMx - Online Access Configuration in the editor window:
The following parameters are available:
| Parameter | Default value |
Value | Meaning |
|---|---|---|---|
| RTS control | Telegram | None | No RTS control (direction control, not for PM55x and PM56x). |
| Telegram | RTS control activated (absolutely necessary for RS-485!). | ||
| RTS/CTS (DTE<->DTE) | RTS and CTS signals are controlled to simulate a DTE device at the PLC communicating with a DTE device. | ||
| RTS/CTS (DTE–>DCE) | RTS and CTS signals are controlled to simulate a DTE device at the PLC communicating with a DCE device. | ||
| RTS/CTS (DCE<–DTE) | RTS and CTS signals are controlled to simulate a DCE device at the PLC communicating with a DTE device. | ||
| Baudrate | 19200 | 300 1200 4800 9600 14400 19200 38400 57600 115200 125000 187500 |
Transmission speed in Baud/s |
| Parity (read only) | None | None | Parity setting for the Online Access. This parameter is read-only (not editable). |
| Data bits (read only) | 8 | 8 | Number of data bits. This parameter is read-only (not editable). |
| Stop bits (read only) | 1 | 1 | Number of stop bits. This parameter is read-only (not editable). |
| Run on config fault | No | No | The PLC program is executed even if there are faults in configuration. |
| Yes | The PLC program is not executed if there are faults in configuration. |
The serial interface settings must match the settings for the serial gateway driver. See Programming via the Serial Interfaces Programming: Programming via the Serial Interfaces Programming and Testing.