We have two licensing models, Multiple Product and Single Product.
The Multiple Product license is designed for manufacturers of end-use equipment, sensors, meters, and other data acquisition hardware. They can use the Modbus library for unlimited number of end-use units for all their products. The price for one Multiple Product License library is USD 1,000.00.
The Single Product License supports design engineers, product developers, consultants and integrators who require Modbus for a single product that they are working on. The library can be deployed on multiple end-use units of the design. The price for one Single Product License library is USD 500.00.
Can we use Modbus for this application?
If the temperature controller that you are using is Modbus compliant then you can certainly use Modbus for this application. This would entail writing an application on the Host PC that acts as a Modbus Master and then communicating with the temperature controllers. If the controllers are not Modbus compliant, then you cannot use Modbus here unless ofcourse you are the designer of the temperature controller and so have the option of adding this support to it.
How to do it? Can it be a cost effective solution? What are the steps involved? Do we require any additional Hardware/Software?
If the controllers are already Modbus compliant, then all you need is a Modbus Master library for the host. You can then write your application in VC++ or VB or C# using this library and do all the application logic you want to. Alternatively, there are SCADA applications that already support Modbus and you could use them if you do not want to write software at the C/C++/C# level. If you are the designer of the controllers and would like to add Modbus functionality to it, then you need a slave library for the micro controller used in your product. The only additional hardware that I think you will need is an RS485 card for your host PC. You can also use a USB to RS485 converter for this purpose.