BECKHOFF EL600x/EL602x Serial Port Module Debugging Manual

Reset 'Send request' (can be reset immediately, terminal module has locked data).

Reception (terminal → controller):

Waiting for 'Receive request' to be set.

Read the 'Input length' and data area.

Set 'Receive accepted' to confirm.

Reset the terminal module to 'Receive request' (prepare for the next frame).

Common Troubleshooting Ladder Table

Possible causes of fault phenomena, priority troubleshooting steps, advanced measures

The terminal module cannot enter the OP state due to ESI version mismatch or PDO configuration error. Check the EtherCAT state machine and check the AL status code; Rescan and verify the revised version to check if the CoE in the Startup List is written correctly; Restore factory default (0x1011:01 Write 0x64616F6C)

Serial port has no data receiving baud rate/data frame mismatch; Wiring error (RS485 polarity reversed) Use an oscilloscope to measure Tx/Rx levels; Confirm that the setting of CoE 0x8000:11/15 is consistent with the device and check if the terminal resistance is missing (RS422 remote requires 120 Ω); Check the 'Enable half duplex' mode

Data reception garbled or byte loss transmission rate optimization turned off, resulting in each byte being uploaded separately; EtherCAT cycle too long to enable 0x8000:05; Shorten the cycle time or increase the receiving buffer threshold to check if the "Explicit Baudrate" frequency error is less than 0.6% (using integer baud rate)

RS485 bus communication conflict: Improper half duplex mode setting. The terminal module receives data sent by itself and sets x800:06=1 (half duplex) and x800:07=0, and sets mode 10 to check the bus terminal resistance position; Confirm that only two end devices are connected to the terminal

Failed to send data. Send buffer full (128 bytes). Check if "Send continuous" is enabled; Confirm the completion of the 'Send accepted' handshake to increase the EtherCAT cycle time and give the terminal more processing time

TwinCAT scans for unknown devices with missing or outdated ESI files. Use 'Update Device Descriptions' to obtain the latest ESI. Check' Show Hidden Devices' and select compatible revision versions

After firmware update, the module does not respond. Download incompatible firmware or interrupt to try to re-enter BOOTSTRAP mode (see below). If there is no response, return to the factory for repair

Firmware updates and version compatibility

The firmware and hardware versions of EL600x/EL602x must match. The document lists a detailed compatibility table (EL6001 HW03-17 can run FW05~16). Important rule: High version firmware is usually backward compatible with lower version hardware, but the opposite is not necessarily true. Before updating, it is necessary to confirm the hardware version (see shell serial number or CoE 0x1009).

Firmware update steps (TwinCAT):

Set TwinCAT to Config/FreeRun mode.

Switch from the station to BOOTSTRAP mode (via the "Bootstrap" button on the Online tab).

In "EtherCAT" → "Advanced Settings" → "ESC Access" → "Firmware Update", select the. efw file (if it is bundled firmware, password=1 can update ESI at the same time).

Wait for the progress to be completed, do not turn off the power or network.

Switch back to Initiat → PREOP, power off and restart the module, check CoE 0x100A to confirm the new firmware version.

FPGA firmware update (*. rbf) is applicable to terminal modules with FPGA (such as early EL6001). The operation path is similar, but it is necessary to confirm that the FPGA version is ≥ 10 (E-Bus terminal) before updating online, otherwise it needs to be returned to the factory.

Factory reset: Double click 0x1011:01 in CoE Online, write the hexadecimal value 0x64616F6C (ASCII "load"), and restore all backup objects to their default settings. If the terminal module is older (before 2007), you can try 0x6C6F6164.

Advanced features: LIN master station support and command mode

8.1 LIN master station auxiliary function of EL6001 (FW10 and above)

EL6001 can simulate LIN bus master station frame transmission at RS232 level. Enabling method: Write 0x3000 in CoE 0x8000:01 (command object), and then the terminal module will automatically insert a 13 bit synchronization interrupt and synchronization byte 0x55 before sending data. Automatically remove these fields upon receipt. This feature does not include a complete LIN protocol stack and only provides physical layer assistance. It requires the PLC to implement PID and checksum calculations. An additional RS232-LIN level converter is required for use.

8.2 Command Mode (MultiDataFrame)

EL6021 FW06 and above support switching encoding modes during the transmission process. For example, the first n bytes use Mark Parity, and subsequent bytes use Space Parity. Write specific values through command object 0xB000 (0x2001 enables multi frame, 0x2100+encoding A, 0x2200+n, 0x2300+encoding B), and then trigger Send continuous sending.

Notes on TwinCAT Virtual Serial COM Driver

If using EL60xx as a standard COM port for Windows (via TcVirtualComDriver), please note: