Multiple USB <-> UART converters - how many can I use on one PC?

[tomeeh]

Hi,

I need to interface lots of microcontrollers to a single Windows PC. How much - 100 pieces. All of them have UART, of course; but USB is not available. I was wondering if I can use 11 USB Hubs, each with 10 output ports connected in daisy chain.
PC
|
1to10 USB HUB
|
10x 1to10USB HUB
| | |
ch.1 ch.2 .... ch.100

Moreover every channel (from 1 to 100) would have a USB to UART converter (FTDI or PL). But I am asking myself if
1. A PC is capable to handle 100 virtual COM ports. (Theoretically it should be 127USB and 256COM ports)
2. 100 pieces of FTDI or PL chip can harmful work on one system...

Any ideas?

 

[arbj2]

maybe possible, it depends on the motherboard of the PC, you would need to use a powered USB hubs for this.

A better option would be to use a RS 485 network. For this you only need one COM port connected to a RS 485 adapter (there are many available online), the network is connected to a RS 485 transciever IC, such as the SN75176. The transciever then sends/receives the data to the PIC serially on TTL levels.

With this option the PC can individually address each micro-controller and read data. You need to implement a suitable protocol for transferring data in packets. Try searching the internet for more on RS 485 protocols.

thanks
a