Issues with the RS485 Shield for Raspberry Pi

Hello there, I apologize if there is already such topic somewhere in this forum, but we’re kinda in a hurry. After following the instructions on how to connect the Shield to the Raspberry and watching many tutorials online on how to make the two comunicate, we are still encountering issues receiving data from a Modbus Slave. As tool for testing the communication we used Modpoll, before trying with Node-Red . We have no clue what the issue could be. Do we need to configure the GPIO18 pin? If so, how? Any help would be greatly appreciated!

Have you tested that your Modbus Slave is working properly?

We did, we tested it using a USB Serial Coverter and yes it’s working just fine.