[FUN] Devicenet/FF Testing of Discrete Valve Controllers

[Stephen Mitschke]

I'd like to get comments/opinions from anyone who may have done testing ofDiscrete Valve Actuators, and evaluated the performance of those on FF H-1'sversus on Devicenet. I have been looking at Tyco's AVID discrete valveactuator, and it has the option of existing on either bus, my preliminarythought is I might get quicker response from Devicenet and I can have moreof them on that bus than on separate H-1's. Any thoughts/comments areappreciated.Jay KalinowskiOCWD

[Stephen Mitschke]

Where does the originating signal come from? If you have on/off valvestriggered by high levels or something else detected by process instrumentsthat site on an FF H1 bus, then having the on/off valve on the same buswould make good sense since you can implement it all using a single bus andyou don't need a PLC or something in between so you get single loopintegrity. In general I feel that not having to mix different bustechnologies is a good thing. Using a single bus technology the deviceconfiguration, control strategy programming, and asset management will mostlikely be much more homogenous.You may also want to check if the device can provide the same diagnosticsand other information regardless of the bus used. It may not be so.Jonas BergeSmar

[Stephen Mitschke]

Good point, but the control of these valves will be by a Delta V controllercommunicating to the various discrete actuators. Due to VCR limitationconstraints on that system, I can't put all the desired devices on the samesegments, multiple segments will need to be utilized. I do, however, wantthe diagnostic capability provided by FF versus what that actuator iscapable of providiing on Devicenet, so they WILL all go on FF, it's just amatter of configuring my segments accordingly.Jay KalinowskiOCWD