Electromagnetic flowmeter settings
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There is an electromagnetic flowmeter, and it is required that the unit displayed in the control room be T/H. How should this be set? It seems that the range unit option in the meter does not include T/H; the available units are volume flow rates such as L/H, M3/H, etc. Does the density of the medium also need to be set? Should this be done within the meter itself or in the DCS system?
There are two solutions: 1. In the DCS, use the density value as a signal for the compensating flow rate to perform density compensation on the volumetric flow rate, so that its display can be converted into mass flow rate. 2. The mass flow rate of the flowmeter is calculated based on the density of the medium; the flowmeter is still defined as a volume flow rate, but the display in the DCS is reset so that the full scale corresponds to the volume flow rate converted into a mass flow rate. Both of the above methods assume that the density is constant. If there is a change in density, it can only be reconfigured in the DCS through the relevant calculation modules.
To perform calculations in DCS, if the medium density is stable, simply multiplying by a fixed coefficient will suffice. If the medium density is unstable, it must be measured again before it can be used in the calculations!
Since mass flow rate is needed, why wasn’t a mass flow meter used from the start? Now it can only be done in DCS as well.