GS1B-ECS-MR03 | Packaging Line: One Gateway for Barcode Scanners, Weighing Indicators and Inkjet Coders
On the EtherCAT production line of a packaging machinery manufacturer, barcode scanners, weighing indicators and an inkjet coder connect to the control system through a single GS1B-ECS-MR03, with all existing devices retained.
Project Background
A packaging machinery manufacturer's automatic packaging line uses EtherCAT as the device-level bus, with a Beckhoff CX series controller as the master; the servo axes and remote I/O all sit on the EtherCAT network. Three types of serial devices are also installed on the line: station barcode scanners, weighing indicators and an inkjet coder (all with RS485 interfaces).
Challenges
- All three device types only provide RS485 serial ports (Modbus RTU) and cannot be connected to the bus network directly as EtherCAT slaves
- Replacing them with equivalent devices that have EtherCAT interfaces would require new selection and validation, at unacceptable cost and lead time
- The packaging cycle is fast, so barcode and weight data must be uploaded periodically and reliably, with no data loss allowed
Cycle-Time Bottleneck Caused by Queued Data on the Three Channels
The project initially used a serial gateway from an overseas brand, in which the 3 serial ports shared a single polling mechanism: barcode, weight and inkjet data were processed in sequence, and collection only started after the PLC issued commands one by one. As soon as the packaging cycle was sped up, missed barcode reads and delayed weight values appeared.
After switching to the GS1B-ECS-MR03, the 3 channels work fully in parallel and poll independently; a change in the polling cycle of one channel does not affect the other two, and data collection no longer depends on commands issued by the PLC — the three data streams each run their own way, and no missed reads occurred after the cycle time was increased.
Solution
A single GS1B-ECS-MR03 three-port protocol gateway is used: on the EtherCAT side it connects to the master as a standard I/O slave, and on the serial side it provides 3 mutually independent RS485 channels, with a total of 6 devices of the three types distributed across the 3 channels.
- Channel 1 — 3 station barcode scanners: read the current barcode on the station trigger signal
- Channel 2 — 2 weighing indicators: the gateway polls the weight values as a Modbus RTU master
- Channel 3 — 1 inkjet coder: send print content and read back device status
Key Parameters
| Item | Setting |
|---|---|
| EtherCAT side | Standard I/O slave, configured in the master using the gateway's ESI file, process data area mapped as required |
| Serial channels | 3 × RS485, each channel configured independently (channel 1 at 115200 baud, channel 2 at 9600 baud, 8N1) |
| Number of slave devices | 6 (3 barcode scanners, 2 weighing indicators, 1 inkjet coder) |
| Power and mounting | DC 24 V (±5%), 35 mm DIN rail mounting in the control cabinet |
Results
- All existing serial devices of the three types (6 in total) are retained; the retrofit only requires adding one gateway in the control cabinet
- Barcode, weight and inkjet data all feed into the master controller, with no impact on the packaging cycle
- The 3 channels can be configured independently: replacing any device later only requires adjusting the parameters of the corresponding channel, without affecting the other two