Magnetic Flow Sensor 8721 Ambient Temperature Effect


I was going through the datasheet of Emerson Magnetic Flow meters and came across the performance specifications of 8721 Sensor. It says as following:

Ambient temperature effect:     ±0.25% change over operating temperature range

So, in order to calculate the impact of ambient temperature, we need to know what is the reference ambient temperature on Emerson side. So, what I think I have to subtract that reference ambient temperature from my site ambient temperature and multiply it with 0.25%. Can you please confirm this? Can you please also provide reference ambient temperature on your end.

  • Hello Shaiq,

    Two things:

    1)  First, the ambient temperature effect only applies to the mag electronics - which are responsible for interpreting the raw flow signals and translating them into outputs.  The flow sensor (or mag tube) may have a more limited temperature range due to lining materials, hazardous approvals, or other factors.

    2)  With that in mind, all of our 8712 and 8732 Series Mag transmitters are oven tested over a range from -40 to 185 F (or -40 to 85C).  This range represents the "factory" denominator you'll need when trying to calculate the ambient temperature effect in your environment.  Under otherwise stable ambient conditions, the magnitude of this effect goes to zero.  However, as the temperature of the internal boards changes with the changing environment, there can be gradients in the measured circuits that cause minor offsets.  The effect of that changing temperature can be characterized as follows:

                    (Amax – Amin) / (Afull) * 0.0025 * 100%


                    Amax = maximum ambient temperature

                    Amin  = minimum ambient temperature

                    Afull = full factory characterized range (225 F, or 125 C)

         For example, if your meter is in an indoor lab-type environment with climate control, it would be rare to experience temperature changes greater than maybe 15 or 20 F.  So the ambient temperature effect would be:

    (80 F - 60 F) / 225 F *0.0025 * 100% = 0.022%          a near negligible amount in terms of flow control or signal stability.

    Feel free to reach out to with any other questions you may have on this topic (or others).

    Thanks,  Jared