Honeywell PHD & History module - Honeywell TPS system


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We have Honeywell TPS system (R680), currently we have process tags historized in PHD & History module. We are planning to remove the process tags configured in History module & start effectively using the PHD tags for panel operators monitoring purpose. Purpose is to reduce the LCN network load.

I still believe that the important process tags needs to be historized in History module as well, because of the fact that there is a time delay (< 60 secs) for PHD tags.

Can any one summarize the advantages of historized process tags in History module over PHD (plant historian database) for panel operators monitoring purpose.

I don't understand your argument about a time delay for PHD tags. You can have PHD scan your tags every 20 seconds, just like the H.M. does, or you can have it go faster or slower if you want to. I don't see a reason to keep continuous history in the H.M. when you have PHD unless you have redundancy in the H.M. and are not using RDC nor RAID on PHD.

Doesn't keeping this history in the H.M. make it more difficult for the operators to know which values are in the H.M. and which aren't ?
Anyway, call-up of PHD trends is a lot faster, has more capability (e.g. hairline) and has much more storage capacity.
We are on R534 with US's only, so our issues may differ from yours, but...

1. HM data can be integrated in operating graphics, in trends or averaged values.

2. A historized tag id can be selected and trended quickly by selecting the Trend button.

3. Free Format Logs.
What Rudi said.

Basically, if you have a reliable PHD or any similar current historization package, go with it. Why bother with legacy HM history that was designed years ago.
Great question.

The history module is more closely integrated with the Honeywell TPS/TDC system than is PHD. For example, trending and other operations can more easily be done from within Native Window (or using US stations) via the history module than via PHD.

If Honeywell's Process Trend (Or another trending tool like Uniformance Process Studio) has not been commissioned for use by the board operators, it will be difficult to view or call up the trends quickly and easily.

As far as time delay, Rudy is right. At the instant that the value is collected in PHD from the TPS system, it is correct and current. However, after collection, the snapshot taken begins to "age". To compensate for this, the collection frequency can be decreased -- down to 1 second if necessary. However, as your desire is to reduce the load on the LCN network, you will have to decrease frequencies judiciously (Perhaps increasing other frequencies to compensate).

There are many advantages to using PHD over the History Module, but as this was not your question, I will hold off on addressing these. Feel free to contact me off-line if you have other questions. Good luck my friend,

Jason Baum