Re: [foxboro] Increment Values
- From: "Johnson, Alex (Foxboro)" <ajohnson@xxxxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Wed, 16 Feb 2005 19:06:37 -0500
The key is the use of a range or Range Variable (Rxy).
The Range Variables (Rxy) parameters are OM objects that contain 3 floating
point values.
Rxy[0] - High scale - HSCxy
Rxy[1] - Low scale - LSCxy
Rxy[2] - Change Delta - DELTxy
The DM/FV is smart enough to set the big (double arrow) and small (single
arrow) ramp buttons to a percentage of the span IF the Rxy parameter is
specified on the tag name, e.g.,
C:B.SPT|RI1
Might be used for a PIDA block setpoint ramp.
If the Rxy parameter is not specified, a default is assumed and the RAMP
Buttons will use a percentage of that span.
If you want a custom span, you can specify it as follows:
C:B.P|R=<lowRng>,<hiRng>
So, try this:
Make a graphic that contains a rectangle. Configure the select action ramp
with the following line:
C:B.SPT|R=2.0,98.0
Protection Class: 0
+/- percent control range: 5
Where C:B.SPT refers to some PID block setpoint in your system.
This configuration will clamp the .SPT between 2.0 and 98.0 Obviously the
custom range should be within the block's RI1 (LSCI1,HSCI1)
****** Thanks to Leo Moramarco/FoxCanada and Ignacio Queirolo Olivera/Repsol
for some of the material above.
Regards,
Alex Johnson
Invensys Process Systems
Invensys Systems, Inc.
10707 Haddington
Houston, TX 77043
713.722.2859 (voice)
713.722.2700 (switchboard)
713.932.0222 (fax)
ajohnson@xxxxxxxxxxx
-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On
Behalf Of Hegewisch, Dirk
Sent: Wednesday, February 16, 2005 8:28 AM
To: foxboro@xxxxxxxxxxxxx
Subject: [foxboro] Increment Values
Hi Group.
I want change the value of an given C:B.P.
The value should change up/down from current value.
For example in +/-0.5 steps (newvalue =3D oldvalue + 0.5)
The ramp function isn't the right function. Because the C:B.P increase
by percent of the control range.
Has anybody an easy solution for this small problem?
Dirk
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