Hi Minhkey, welcome to TMC.
As Bruce has said you can use the RoastLogger to read your roasters display directly. You would be surprised how many commercial roasters do just this to avoid installing thermocouples.
Real time logging and charting of temperature profiles including comparing the progress of the current roast against a chosen profile is relatively easy to achieve. The main items required to achieve this are as follows:
1. A thermocouple reading bean temperature. I understand from your post that you already have this.
2. Optional but highly recommended would be an additional thermocouple reading the environment temperature.
3. A device that can read the thermocouples and communicate the readings to a computer
4. Software on the computer that can communicate with the device in 3. and log and chart the readings
There are many issues affecting the choice of equipment and I would recommend that you do your homework by reading relevant posts on this and other coffee forums in particular read through the last several pages of the RoastLogger thread and the Artisan thread in the sticky section above your post. The main issues to consider are:
1. The type of thermocouple to use. K type thermocouples are the most common and cheapest and are adequate for this service.
2. There are a number of devices that can read the thermocouples and communicate the data to a computer. I would strongly suggest you decide on the software you wish to use first then read up on what devices are compatible with that software.
3. For the software to use there are a number of commercially available systems or you can use free software designed for coffee roasting such as the RoastLogger or Artisan mentioned above. I would suggest that you read up on these software options. If you decide to use free software then I suggest you download and run the alternatives to decide what will work best for you.
My advice would be to use a TC4C (you will see links to this on the RoastLogger website). This is designed specifically for coffee roasters, is very reasonably priced, provides temperatures to tenths of a degree, provides excellent rate of rise information, is very flexible and can be programmed to work with either RoastLogger or Artisan. The only difficult task would be to select and install suitable thermocouples. Once this is done you simply connect the thermocouples to the TC4C connect the TC4C to the computer with a USB cable and install and run the chosen software.
The TC4C can be programmed to work with different types of thermocouple and different software but this can be a daunting task if you are not familiar with programming an Arduino. It is, therefore, advisable to select the thermocouples and decide on the software first then order a TC4C programmed to work with these.
Computer control of a 60 kg gas roaster would need to be done very carefully to avoid serious safety issues and I would strongly suggest you would need expert professional advice for the specification and installation of such a system.