Arduino Modbus RS485 and GSM interface coding problem.

Hello everyone !!!
I have been working on a project to built an remote monitoring system for modbus devices.
Hardware part is ready and working fine but a problem I'm facing is related to coding part especially coding syntax. I had 2 different codes working fine when individually, but i had to merge them into one . I did it just fine considering all the variable etc. Now problem I'm facing is i have to run 2 loops i.e to fetch data from modbus and send it for monitring and secondly check for a ring and send the current co-ordinates to the defined number. But when Arduino goes fetching data it never comes out of loop hence even after receiving a ring it doesn't send co-ordinates, instead it keeps on fetching data continuously.
Kindly help if you have any idea regarding this . Thank You in advance :slight_smile:

I just need to know how my approach should be in order to run two loops parallely.