Issues regarding the pulse signals of electromagnetic flowmeters
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Regarding field instruments, the electromagnetic flowmeter outputs a pulse signal PLS; is it necessary to take into account this special I/O type when selecting the I/O module? Should I just use a regular DI card (for counting)?
In TPS systems, either Pulse Input or Digital Input can be used; our factory only uses PI when the frequency is high
Generally, modern electromagnetic flowmeters output standard signals; for example, Yokogawa’s electromagnetic flowmeters produce 4 to 20 MA standard signals. Only instruments used for measuring rotational speed output frequency signals. The CS 3000 we use has a dedicated module for processing frequency signals, rather than relying on ordinary DI inputs.
What does high frequency mean? Could you explain it in detail? Thank you. I know that many manufacturers offer input cards designed specifically for pulse signals. Considering costs, if ordinary DI cards can be used, then those are obviously the better choice, as they also make it easier to obtain spare parts.
The Pulse Input card of the TPS system can receive pulse signals up to 20KHz, but the PI card is more expensive than the DI card; for frequencies below 10Hz, we use the DI card to receive them! Electromagnetic flowmeters, belt scales, smart electricity meters, etc., can generally output both mA and pulse signals; the pulse signal ensures that the figures displayed on the meter match those on the DCS!