Ramping a analog output

pincho · Jul 1, 2010

Hello

I have a small problem i have done program for hydraulic unit
So one regulation valve is controlled in 4-20 mA to extend or retract a cylinder
The client want that this signal is ramped when press start and also ramped when release start
I have done something but it is not working very fine
If someone has a tip thanks in advanced
Language is ST (IF ... THE? ... ELSE)

BYe

Roy Matson · Jul 2, 2010

One way to ramp is simply increment / decrement by a fixed value each scan or time period
IF Y < X LET Y = Y + Z
IF Y > X LET Y = Y - Z
Kind of thing, I know I don't have the sintax correct
I suspect you have done this already

KalleOlsen · Jul 2, 2010

If it is an S7 you are fighting, look at this link to oscat. In there you will find a library with a ramp function with speed and acceleration parameters. The source code is also there.
K

pincho · Jul 2, 2010

Thanks for you comments

I wil try somethind like yous tell
No i m using ABB ACS 800

Bye

bits'bytes · Jul 2, 2010

Hello,

usually I use a timer FUB together with a scale FUB for that.

Code:

scale.X1 = 0
scale.X2 = time
scale.Y1 = ramp_min
scale.Y2 = ramp_max

putting the timer elapsed time on the scale input gives the corresponding ramp value on the scale output.

br
bb

TConnolly · Jul 2, 2010

The equation for a ramp is

Beginning_Point + ((Ending_Point - Beginning_Point)*Elapsed_Ramp_Time/Total_Ramp_Time)

Paul B · Jul 2, 2010

KalleOlsen said:
If it is an S7 you are fighting, look at this link to oscat. In there you will find a library with a ramp function with speed and acceleration parameters. The source code is also there.
K

Thanks for the link!

Ramping a analog output

pincho

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Roy Matson

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KalleOlsen

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pincho

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bits'bytes

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TConnolly

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Paul B

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