Limited PID gain to 127 for FPGA

[Rayden]

Hi,

i have tow questionq the first is technical the second is commercial.

1* For an FPGA application with PXI8108 and PXI-7841R i want to insert a value of "2100" so higher than 127 but pid module gain is limited to 127.

How can i do. thanks for your help  😕

2* I want to buy another  product like FPGA target PXI-8108 for others application but i need only PXI7841R with LABVIEW FPGA and RT i d'ont need to other complementary modules to insert . The chasis it's neccesary ?

I can not find other versions like PXI7841R do the same job with the same performance with PC but less expensive (without chassis & PXI-8108)  ? i'am looking for in NI site,but i did'nt found so can you propose me some NI desired product 

thanks for all your responce.

Riadh ABDELHEDI.

[Sam_Sharp · Accepted solution]

2) The chassis has the RT controller. You can get R-series FPGA cards (no RT) for USB / PCI / PCI-Express which would plug into a regular PC. You can install LabVIEW Real-Time on a PC but it requires certain hardware configurations for it to be supported. Have you  considered a RIO device like a CompactRIO / sbRIO? These are small form-factor embedded NI devices that have an RT controller and FPGA and are lower cost than the PXI-based solution.

[Barp]

The PID FPGA that you are using is fixed-point and the maximum available is 127. If that is the proportional gain, than you can always multiply 16.5 the output, to obtain the additional gain. Or prescale the setpoint/process variable to this amount too.

If you have access to LabVIEW FPGA 2015, we have a floating-point PID that would allow you to use any value that you'd wish (within the single datatype).

[Rayden]

I use Labview FPGA 2014.

Can you explain more please... i see many solutions but what i must do exactly to put a value over 127.

Thanks.

[Rayden]

@Sam_Sharp

I have a budget of 1500 euros what can i buy as Compact RIO model to developp application about control power electronics converter,some others E/S...

thanks to sugess me some commercial links.

[Sam_Sharp]

This is a conversation you should have with your local NI Sales Representative - call your nearest office and discuss with them as they can select the right product for you given your budget.

Without knowing your exact input/output requirements I couldn't possibly select something - a Single-board RIO (e.g. 9636) or cRIO (9066 or 9063) with a few modules might be the best things to look at.