Re: [foxboro] AIN Block / Deadband

That's a data value deadband for reporting to data users such as display =
graphics and historians. That is obviously not going to work. You need =
to use an alarm parameter and limits to turn your equipment on and off. =
Use the deadband of the alarm to prevent that bounce.=20

The real way you should approach on-off control is with a differential =
gap controller. Use the measurement from the AIN and se the setpoint of =
the gap controller as the equipment on-off point. The output of the gap =
controller is on-off that you feed to the discrete output that controls =
the equipment. Look up DGAP controller in the control documentation.

* K


> -----Original Message-----
> From: Livingood, William [mailto:wlivingood@xxxxxxx]
> Sent: Friday, May 21, 2004 9:48 AM
> To: 'foxboro@xxxxxxxxxxxxx'
> Subject: [foxboro] AIN Block / Deadband
>=20
>=20
> Based on the output from an AIN block, I am turning on/off=20
> equipment.  The
> value from the AIN block sometimes lies right near the=20
> threshold for turning
> on/off the equipment.  The result is that the value from the AIN block
> "bounces" above and below the threshold causing the equipment=20
> to turn on and
> off rapidly.  Looking at the AIN block documentation, they=20
> have a deadband
> category (DELT01), BUT the documentation suggests that it is=20
> not functional.
>=20
>=20
> Does anyone have a simple way to send the output of the AIN=20
> block through a
> deadband feature?
>=20
> ~Bill
> =20
> =20
> ______________________________________________________________
> _________
> This mailing list is neither sponsored nor endorsed by=20
> Invensys Process
> Systems (formerly The Foxboro Company). Use the info you=20
> obtain here at
> your own risks. Read=20
> http://www.thecassandraproject.org/disclaimer.html
> =20
> foxboro mailing list:            =20
> http://www.freelists.org/list/foxboro
> to subscribe:        =20
> mailto:foxboro-request@xxxxxxxxxxxxx?subject=3Djoin
> to unsubscribe:     =20
> mailto:foxboro-request@xxxxxxxxxxxxx?subject=3Dleave
> =20
>=20
 
 
_______________________________________________________________________
This mailing list is neither sponsored nor endorsed by Invensys Process
Systems (formerly The Foxboro Company). Use the info you obtain here at
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
 
foxboro mailing list:             http://www.freelists.org/list/foxboro
to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave

Other related posts: