Hardware needed to control 100 PC fans

[Marshall1717]

Hello,

I am fairly new to picking National Instruments products and I am a bit confused about the hardware I need. The project I am working on requires 81 PC fans to be independently controlled with PWM using the clock on board the chassis (not software based timing). I will be using a cDAQ-9174, cDAQ-9178, or cDAQ-9179, depending on how many modules I need. From my understanding, I will require modules that can access the chassis' on-board counters. According to the link below, the most channels I can get on 1 module with access to the on-board counters is 8. 

http://www.ni.com/product-documentation/54453/en/#toc2

My main questions are;

1. Is it true that I need modules with access to the on-board counters to produce the PWM signals for the fans? If not, can I use a simple C series Digital Module like the NI 9476?

2. Will I need to use a module that has 5V/TTL outputs to control PC fans?

Thanks in advance for any input.

[Tepig]

Marshall1717, you are correct.

Each Digital Module have more than 8 channel but actually, those devices don't have counter feature.

Chassis has, so Modules are just accessing the circuit.

As a conclusion, you cannot resolve the limitation even if you use DIO module.

Umm... I think cDAQ doesn't satisfy your requirement, it should be very expensive system...

Why don't you try FPGA? cDIO + DO module can generate PWM from each DO channel.

PWM Output With LabVIEW FPGA

Example: FPGA PWM Variable Duty Cycle & Frequency generation and measurement

[Marshall1717]

Hi Emboar,

Thank you for replying. I took some time to look into the example you sent me. I have not dealt with FPGAs before, but they seem like they may be a good option for what I want to accomplish. However, the NI Veristand is a bit out of budget for my project. I was thinking of using a NI-9146 cRIO chassis with three NI-9403 C series modules. With this set up, will I be able to output 81 PWM signals at 25KHz?