Re: [foxboro] FBM241 - input pulse rate
- From: cleddon@xxxxxxx
- To: foxboro@xxxxxxxxxxxxx
- Date: Wed, 18 Apr 2012 08:51:04 -0400 (EDT)
Seems to me that you will end up with a much more reliable solution with less
engineering time if you purchase the the module designed to do the task as
opposed to rolling your own. What happens if you leave and someone else has to
modify the code you wrote? As I get older (50 < x < 100) I am less inclined to
use customs as opposed to off the shelf components. You will burn through the
cost of the FBM in engineering hours while you are testing code.
Chuck Leddon
-----Original Message-----
From: Ken Heywood <KHeywood@xxxxxxxxxxxxxxxxxxxxxxxxxx>
To: foxboro <foxboro@xxxxxxxxxxxxx>
Sent: Tue, Apr 17, 2012 12:59 pm
Subject: Re: [foxboro] FBM241 - input pulse rate
Ah, the horse lives. Yes you can count pulses, but then you must determine
rate.
ou are still at the mercy of the BPC. At such slow rates as 10Hz, it may be
etter to measure the period of the on or off state (assuming 50% duty cycle)
nd then calculate the rate in a CALC block as the inverse of that period.
hank You,
en Heywood
alibration Laboratory Manager
PROCESS CONTROL SERVICES, INC.
stablished in 1983
http://www.processcontrolservices.com
mailto:KHeywood@xxxxxxxxxxxxxxxxxxxxxxxxxx
elephone: 734-453-0620
ireless: 508-241-2040
===============================================
-----Original Message-----
rom: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On
ehalf Of Douglas G. Lloyd
ent: Tuesday, April 17, 2012 12:23 PM
o: foxboro@xxxxxxxxxxxxx
ubject: Re: [foxboro] FBM241 - input pulse rate
Ken/Dirk,
Not to beat a dead horse, but you could use PLB logic in the FBM241 to avoid
the
P BPC issue. Pulse capture resolution (using PLB counters) is then up to the
rocessing speed of the PLB logic (5-10msec?) and the actual FBM
ardware/software...
Regards,
oug
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