Replace RS-485 with Siemens Profibus Cable

Hi there. I am building a Modbus RTU network. I have 82 energy power analyzers. Different brands. Though 80% of them are Circutor (Spain manufacturer). All of them old models. By old i mean probably 10 years old. All of them have Modbus RTU available. The ones who have not will be replaced by probably Schneider line of low cost meters.

I have distributed them into 5 branches, all of them with less than 31 meters. I am looking for cable. Local suppliers (i am in South America) quote RS485 cable for 7 dollars meter. I can buy Profibus cable from Siemens by 3 dollars/meter. my network has an estimated lenght of 2000 meters. The largest branch has 500 meters of cable. Since I am in a budget, i am trying to balance cost of software, gateways, cable, and so on.

I am tempted to use Profibus cable since it is bases on RS-485 standards and is half the price. and i consider Siemens a serious company. Any comments? Anyone can share with me an experience of using this trick. Success or failure stories will be very welcome.

Hello, apparently this guys are Siemens Distributors for South America:

They have the RS-485 published in their website.

I contacted them before for other parts and they answered quickly.

Maybe they can provide you the cable or guide you in the process to find a solution.