Like Corey, we have converted all versions of PID,E,X,XE to PIDA's and are gradually converting from PLB, MTR, and VLV blocks to GDEV's. We have modified the default GDEV faceplate into a generic format for each specific function. One for Motors/Pumps, a different one for on/off block valves, and another for 3-way valves that only have two possible flow paths. My only complaint about the GDEV is associated with the motor start/stop functionality. We have a lot of Hand/Auto switches on pumps and motors in the field and in many cases we only have one DCS COUT used to both start and stop a motor and one CIN for RUN Status. Using ladder logic we pulsed the start and sealed around it with the RUN Status contact to hold the COUT until we pulsed a stop or the RUN status failed. We wish the GDEV could pulse the start using the pulse option and then use the feedback from the run status, (.DEVLM2) to latch in .COUT_1 just like a seal in , (AUX), contact would do in wiring in the field. If .DEVLM2 went false while the request to run, (.MANDSR or .AUTDSR), was still true then the GDEV would issue a Mismatch alarm and drop .COUT_1 and the .MANDSR or .AUTDSR request so the MTR could be started again without first having to pulse a stop and then pulse a start to restart. The MTR block has a function that is close to this but it doesn't work with the PULSE option. I'd write a CAR but my past experience tells me that an enhancement to a block function is even less likely to get done than fixing a bug, so why bother. Brad, when you are talking about a valve with two solenoids and only two limit switches how do you tell if the valve is half open and how do you hold it in that position? Do you wait until neither limit is made and then turn both the COUT's off? We have a call for "Fail Last" valves that utilize two solenoids and two COUT's but have never used a block valve in a three position mode. Cheers, Tom VandeWater Dow Corning Corp. brad.s.wilson@xxxxxxxxxxxxxx wrote: > Yes, I use GDEVs extensively and am converting the numerous VLV & MTR > blocks that uninformed engineers have built over the years. There are > numerous advantages to GDEV, not least of which is STAIND for bitmapping to > display elements. However, I really wish there was 3-state capability. As > I stated earlier, many of our block valves have closed, open & half-open, > and there's no way to accomplish this with a single block. We use a CALC > coupled with 2 CINs for valve limits & 2 COUTs for solenoids. I suppose if > all the valves were wired differently, I could use MCIN & MCOUT, but that's > not the case ... aaargh. > > Brad Wilson > Process Control Engineer > ExxonMobil Chemical Co > Edison Synthetics Plant > 732-321-6115 > 732-321-6177 fax > Brad.S.Wilson@xxxxxxxxxxxxxx > > > > _______________________________________________________________________ > 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: //www.freelists.org/list/foxboro > to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join > to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave > > _______________________________________________________________________ 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: //www.freelists.org/list/foxboro to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave