16.I am using 4 PR-E extensions, but they has no function, the indicator flashing red, how I make it works?

16.I am using 4 PR-E extensions, but they has no function, the indicator flashing red, how I make it works?

The indicator flashing red means the extension cannot communicate with CPU successfully, please check the connection between extension and CPU, moreover, you must confirm the extension
 address of each module is different. Regarding of how to set the address of extension, you can refer to the FAQ1.