CPX-AP-x-4IOL-M12: Working with OE variants in EtherNet/IP
Sandro Quintero, Mechatronics Technology Engineering Manager, Festo North America
TL;DR
When using a CPX-AP-x-4IOL-M12 module on an EtherNet/IP network, it is recommended to use the non-OE Variant for selecting the port size. This way, you won’t have to deal with OutputEnable.
Description of OE
When configuring the ports of an IO-Link master like CPX-AP-I-4IOL-M12 or CPX-AP-A-4IOL-M12, you will come across a parameter that specifies the number of bytes reserved per IO-Link port, known as the Variant.
Let’s discuss setting up an IO-Link module for 2 bytes per port in an EtherNet/IP (EP) network. As shown in Figure 1, we have two options: Variant 2 and Variant 2_OE, both of which are supported on EP. The main difference lies in the output size, with Variant 2_OE having an additional 4 bytes.
Figure 2 shows where the Variant is selected when using Festo Automation Suite (FAS), this can also be configured in the WebServer of the IO-Link module.
OE stands for Output Enable and is typically used when configuring the IO-Link master for a PROFINET (PN) network. However, it can also be used in an EtherNet/IP (EP) configuration.
Recently, I encountered a case where the OE variant was selected, and when the user attempted to turn on the outputs on one of the ports of the IO-Link master, the PLC would receive the data, but nothing would happen. It was as if the data wasn’t being sent to the IO-Link device. This occurred because Bit 0 of the OutputEnable byte for that port was set to FALSE. Once that bit was set to TRUE, the data was successfully transmitted to the IO-Link device, Figure 4.