On the signal allocation problem
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A differential pressure flow meter that outputs a 4-20mA signal; on-site, a two-way isolation barrier is used, with one output going to the on-site integrator and the other going to the DCS. Now, I want to obtain another signal route to go to another plant site; I originally planned to use a 1-to-3 safety barrier, but management constraints prevent its use. So, has anyone tried using another 1:2 isolator after the first one to achieve three final outputs? Is such a approach feasible?
Personally, I think it’s feasible; I haven’t verified it. It is recommended to give it a try
There should be no problem with this, as it is a isolated safety barrier, so there are no limitations regarding load.
Typical integrators also have a 4-20mA output; check if yours has one, as it can be utilized if available
I haven’t used it; you can use AO in the system to send it
It can be output through AO; it is not possible to use another isolator after the first one. Isolators or safety barriers cannot be connected in series.
It’s not highly recommended; if the distance is too great, power becomes an issue. Even with a barrier applied, I’m afraid it won’t work. Network communication between DCS systems is still better
It’s a flow meter installed at an external factory; the solution proposed by their cabinet room’s AO is not viable. For now, we’re checking whether the integrator has a flow output signal before making further decisions.
If the distance is relatively large, reassignment of signals can be used, but the accuracy cannot be guaranteed, as it is essentially the sum of the first error and the second error.