BECKHOFF EL600x/EL602x Serial Port Module Debugging Manual

EL602x supports configuration through the combination of CoE objects x800:06 (Enable half duplex) and x800:07 (Enable point to point connection):

00: RS485 half duplex, the terminal module will receive the data it sends (requiring software filtering).

01: RS422 full duplex, point-to-point (default).

10: RS485 half duplex, the terminal module only receives data from other devices (not its own data).

11: RS422 full duplex, but only enables reception after transmission is complete (to avoid echo).

In practical applications, if RS485 multi station is used, mode 10 is usually selected.

TwinCAT debugging process (from scanning to parameterization)

4.1 ESI Device Description File Update

Firstly, ensure that the ESI directory of TwinCAT contains the latest XML description files for EL600x/EL602x. You can download it online through TwinCAT's "Update Device Description File (via ETG website)" function, or download it from Beckhoff's official website and put it in C: TwinCAT 3.1 Config Io EtherCAT. Attention: Different revision versions (such as -0016, -0019) may correspond to different hardware/firmware combinations and must be matched.

4.2 Online Scanning and Configuration

Switch TwinCAT to Config mode, right-click on "I/O Devices" → "Scan Devices", and select EtherCAT devices.

After scanning the terminal module, the system will automatically load the default process data (PDO). For EL6001/EL6021, the default PDO is 22 bytes of user data+1 byte of control/status (corresponding to RxPDO 0x1604 and TxPDO 0x1A04).

If you need a 16 bit process data interface (for 9-bit data or more efficient data transmission), you can select PDO 0x1605 (output extension) and 0x1A05 (input extension) in the "Process Data" tab. This requires firmware version support (EL6001 FW08 and above).

4.3 CoE parameter configuration (0x8000 object)

All communication parameters are concentrated in object 0x8000 (single channel) or 0x80n0 (dual channel, where n=0 is channel 1 and n=1 is channel 2). Key sub index:

0x8000:11 (baud rate): Supports 2400~115200, and can also input any integer value (1000~115200) directly through 0x8000:1B (Explicit baud). The firmware must be ≥ 11 (EL6001) or ≥ 09 (EL6021).

0x8000:15 (data frame): Optional formats include 7E1, 8N1, 8O2, etc., and special formats (such as 9N1) can also be selected through 0x8000:1C (Extended data frame).

0x8000:05 (transmission rate optimization): default enabled. When there are no new bytes within approximately 16 bits after receiving data, the buffer content is automatically packed into the process image to reduce the EtherCAT cycle burden. If the device sends continuously without any gaps, this function should be turned off.

0x8000:04 (Continuously Sending FIFO Data): When enabled, first fill the send buffer with up to 128 bytes, and then trigger continuous sending through the rising edge of the "Send continuous" bit of the control word until the buffer is empty.

0x8000:1A (Rx buffer full notification): Set the "Buffer full" status bit when the amount of data in the receive FIFO reaches 864 bytes by default.

Important: After modifying any of the above communication settings, reinitialization must be triggered through the control word (Init request), otherwise the changes will not take effect. Initialization process: Set Init request → Wait for Init accepted → Reset Init request.

Process data and control word analysis

5.1 Standard Process Image (22 Byte Mode)

Output (Controller → Terminal): Contains control words (low 8 bits or high 8 bits, depending on PDO selection) and up to 22 bytes of data (Data Out 0~21).

Input (Terminal → Controller): Contains a status word and up to 22 bytes of received data (Data In 0~21).

Control word key bits (taking single channel bitwise representation as an example):

Bit 0 (Transmit request): The controller is set to notify the terminal module that "Output length" bytes are waiting to be sent; The terminal module has received confirmation from the rear position 'Transmit accepted'.

Bit 1 (Receive accepted): Set the controller to confirm that the input data has been read; The terminal module can then send new data.

Bit 2 (Init request): Set to initiate initialization, enter ready after reset.

Bit 3 (Send continuous): When continuous transmission mode is enabled, the rising edge initiates FIFO transmission.

Status word key position:

Bit 0 (Transmit accepted): Terminal module confirms sending request.

Bit 1 (Receive request): The terminal module is set to indicate the presence of new received data (length indicated by "Input length").

Bit 2 (Initialize accepted): Initialization completed.

Bit 3 (Buffer full): Receive FIFO full, subsequent data loss.

Bit 4~6: Parity check error, frame error, over limit error.

Bit 8~15: Input length (actual number of received bytes).

5.2 Data Transmission Handshake Process

Send (controller → terminal):

Set the 'Output length' to the number of bytes to be sent (n).

Fill in Data Out 0~n-1.

Set 'Send request'.

Wait for the terminal module to be set to 'Transmit accepted'.