Created Date: February 13,2012

Created by: Gvanauken

If its a poweflex drive there is a accel2 and decel2 in the advanced parameter set....

I don't have a manual in front of me but I believe you can use the different acc dec based on the terminal strip logic of the drive.

so when in product flow you use acc1. backflush acc2.

Edit

There is also a thing called Step logic on the powerflex that allows you you adjust ramp accel speed selection, with time delays etc.. Though I 've never used it.

This seems like possibly a quicker work around.

Created Date: February 14,2012

Created by: plcnut

I'd be curious about how this works out for you, I have a system where I'm controlling a proportional hydraulic valve with variable accel/decel ramps in both directions, I am using the add so many/subtract so many per scan ramps, and I'm not impressed with the results. The PID sounds great, but I didn't have the time to experiment before the system was put into service.

Created Date: February 13,2012

Created by: Cap

I need to come up with a 'software Module ' that I can Call, to Accelerate and Decelerate a VS Pump Motor. The Pump does 'double Duity ', as a 'Product Discharge ' from a Filter, and a 'Backwash Pump ' to clean the Filter every 120 seconds or so... same stuff goes through it.. just Valved Differently. Pump is about 5 HP.. 3 " Tubing, running at about 7000 GPH Speed.. Stuff is Moving!

The problem is, as a Product Discharge Pump, it's Pushing product in Excess of 300 Feet sometimes, and the Hyd Hammer is Loostning the Overhead Clamps of the Discharge Piping. I have turned down the Acceleration rate in the VS Drive to Stop the Hammer, ( I'm in the 4 Second range.. ) and as a 'Backwash Pump ', the Pressure Rise is not fast, and my Cleaning is not as good. I want to have a Quicker Acceleration During Cleanings, to allow me to clean the Filter better to get it back on Line. I'm Living with the Reduced Cleaning Effort for now, to prevent the Overhead lined from falling to the Ground!

I'd like to make a 'slick ' software Module to drop into a Subroutine to controll the Different Acceleration/Deceleration rates for the Pump, depending upon whether it was called by the Backwash Routine, or the product discharge Routine. and I would like the Acc and Dec rates to be Varable from each other.

The VS Pump speed will be Controlled by 4-20 MA output from a 260 to an AB Drive ( Did not select the Drive.. it's in the Machine )..

The Machine is a Wine Filter, and is all automated, for Filtration and Cleaning.. It has some 60 Valves and 13 Pumps.. It's Presently Running an AB PLC, with ALL AB Controls... I'm SLOWLY converting it over to my Software on the 260, and one of the Stumbling Blocks presently is this feature I want to add.. I 've Completly Converted it's Little Brother over to my controls, ( 7 Motors and 20 Valves ) and can test out the Conversion before I jump on to the Big Guy...

I was thinking of using a PID Loop, using Binary Input to trigger the Output to increase or decrease at the Gain speed, and Limit the Output to be the Speed I wanted to achieve on the Pump. This would keep the same acceleration or deceleration Rate, depending upon Different Scann Times.. but this option is not 'Varable ' on the Two Different Rates of Start and Stop.

Presently I do not have any PID Control on this Pump, just a Set point Speed, and run till completion.. then off.. and next time on will be either Cleaning, or Product Discharge..

Any insites to the way you have handled stuff like this before would be helpfull. I have done simple "Add number each scann, and Match " loops , but they rely on Loop Speed and I'd like to make this a little more Swifiticated.. :)

Thanks..

Cap