What are the output signals of the electromagnetic flowmeters?
The output signal of the electromagnetic flowmeter is not single and constant. Under normal circumstances, the electromagnetic flowmeter outputs 4~20mA and sends it to the system for display, or enters the secondary meter for display. This signal is used to display the instantaneous flow. If the flow at this point needs to be accumulated in the system or in the secondary table, then the pulse signal is used.
A pulse signal will correspond to a certain flow value, and then be superimposed in the system to calculate the cumulative flow. Such two signals will not interfere with each other.
Generally, the pulse output mode of electromagnetic flowmeter is mainly used for measurement mode, outputting a pulse, representing an equivalent flow, such as 1L or 1M3. Pulse output equivalent divided into: 0.001L, 0.01L, 0.1L, 1L, 0.001 M3, 0.01 M3, 0.1 M3, 1 M3; ,0.001UKG, 0.01UKG, 0.1UKG, 1UKG, 0.001USG, 0.01USG, 0.1USG, 1USG .
Therefore, when customers choose the pulse equivalent, they need to pay attention to observe whether the flow range of the flowmeter matches the pulse equivalent. For volume flow, the calculation formula is: QL=0.0007854×D2×V (L/S) or QM=0.0007854×D2×V×10-3 (M3/S) Among them, D represents the pipe diameter (mm), and V represents the flow rate (m/s).
If the flow rate of the electromagnetic flowmeter is too large and the pulse equivalent selection is too small, it will cause the pulse output to exceed the upper limit, so the pulse output frequency should be limited to below 2000P/S. In addition, if the flow rate is small, but the pulse equivalent is too large, it will cause the instrument to output a pulse for a long time. So it’s not appropriate in either case
In addition, the pulse output is different from the frequency output. The pulse output is accumulated to a pulse equivalent and a pulse is output, so the pulse output is not particularly uniform.
WESDOM electromagnetic flow meters’ interface as followings: 4~20mA, Pulse, RS485 and Alarm. Apart that, we also can provide Heart and GPRS for your selection.