Dr Byte

Greetings! Thank you for your reply! I will most certainly take your advice and use buffered DAQ/aquire and decimate. I am using three DAQ boards per chassis, a 6031E, a 6025E and a 6704. by spreading the load, I believe I can isolate the critical DAQ from the PIDs, but time will tell! yes I do have 6x21, and it is the P200 (hence my concern). Timestamp/IP source would be an excellent way to tag data on the DS server. Your suggestion of a seperate client on the DS server causes me to imagine one that interrogates the data, scrubs and dumps to the sql server on the LAN when available bandwidth exceeds a min threshold. This is a fun project with loads of opportunities for creativity and learning! Thank you for taking the time to share your thoughts! Best Regards

Thanks for your reply! DS server running on the LAN to facilitate pooled resources with some allocation of transfer rate dependant on IP of RT client would certainly provide a sharing mechanism for process snapshot data! Perhaps using a managed switch with the DS server living behind it would allow bandwidth management for each of the RT clients without requiring any prioritization code on the DS host !? However let me re-state the problem: Picture 6 RT clients, each controlling 6 manufacturing machines, monitoring 21 Analog channels and collecting data on the DS server you mentioned. These clients are also controlling PID loops, communicating with hardware through RS232, analog outs and digital outs. Only one signal being monitored must never be interrupted. The PXI chassis' are fitted with the 8175 embedded controller. All sample rates on Analog input channels are typically set to less than 5Hz. per channel. If the standard deviation of any signal becomes greater than acceptable, I am progressively increasing the sample rate in order to collect more data on the problem at hand. This puts a significant load on the 8175 and alters the amount of resources available to other tasks. I could help reduce the problem by adding RT boards to the chassis' that have their own embedded processors, but the cost of the solution across all of the systems would go too high. What I would like to do is use some sort of Task Prioritization to offload low priority loops to other clients in a pseudo-load balancing manner, where one client would be given a task to perform on another client through the remote clients Analog/Digital/RS232 interface. This would allow all 8175s to share the load of the increased sample rate requirement generated by the excessive standard deviation of the signal in question. If I had a way of monitoring the performance of the 8175s and offloading tasks to those 8175s which have available resources, that would be great!!!! Thanks again for your input!!! Best Regards Dr. Byte

STOP STOP!!! Yer makin' me dizzy!! hahahaha

Greetings! Application: Automation of manufacturing equipment with centralized data collection, multiple PXI chassis' running RT as clients on Microsort Windows 2003 domain. Problem: I have 6 RT client clones running identical programs (each with slightly different configs). I am using dynamic DAQ loop control to monitor 21 analog channels on each client. The collected data is stored locally on each client and dumped at the end of each process step to a SQL database residing on two clustered database servers. During the execution of a step, the data collected is statistically analyzed and if deemed non compliant, the number of samples collected from key signals is adjusted to "zoom in" on the data for problem identification. In the event that a number of channel sample rates are increased concurrently, I would like to pool system resources from other clients to contribute to the stability of other digital/analog activities such as PID loop control and timed activation of digital devices. Is there any way to pool the resources of multiple PXI clients on an "as needed" basis based on an event on one of the clients? Some sort of data shared invoked VI that tracks process status from one client to another? I am pulling out what little hair I have!!!! Thanks in advance Dr Byte