Eaton Durant Eclipse 5775X-40 Series Installation And Operation Manual

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15WIRING cont.Programming Considerations for Flowmeter Input and DIP Switch DefinitionsThe inhibit input will normally not be used. The count inhibit function means that thecounter will ignore flowmeter pulses when inhibit is active. This is handy at sometimes, such as when the system is being purged. However, experience has shownthat most users do not care to use this function. Inhibit inputs on counters aroundthe world are aware of this fact; because of it, inhibit inputs generally suffer from lackof self-esteem. Inhibit inputs are the original Maytag® repairman. Durant is a sensi-tive, caring counter manufacturer that has decided to do something about this. Theinhibit input on the Eclipse is programmable (in block F1, page 26) to either do itstraditional inhibit duty, or to select between two pre-loaded K factors. This opens upa number of application possibilities, some bizarre, some simply clever. If one Kfactor is the number of pulses per gallon and the other K factor is the number ofpulses per liter, the user can go from counting in gallons to counting in liters and viceversa simply by throwing a switch. Gallons to pounds conversion is another likelyscenario.Setting the DIP switches can be an adventure since there are a wide variety offlowmeter types and there is no standard output pulse signal. Furthermore, signalconditioning devices, such as flow transmitters, may change the electrical charac-teristics of the signal. The most common flow signal is a differential, AC voltagegenerated by a paddlewheel flowmeter. This is a two wire signal, and the outputfrequency can easily exceed 200 Hz. Mag pickups are sink and source, so don’tworry about DIP switch 1, just turn 2 OFF and 3 ON. Contact outputs, such as reedswitches, are much less common. They can be set up as sink, as shown in thediagram, or source. Since the diagram shows how to wire them as sinking sensors,use that method. Contact inputs will always be low speed, so switch 2 is ON.Transistor output signals are generally three wire, since the transmitter usuallyrequires DC operating power. The Eclipse puts out 12 VDC for these types of sen-sors. Transistors are either NPN or PNP. NPN outputs are sinking outputs; theyprovide the path to ground. PNP outputs are sourcing; they provide the path to posi-tive. These signals are considered “single ended” because they are referenced tocommon (ground). They can easily be high frequency signals. Switches 2 and 3should be OFF, and switch 1 is OFF for PNP, and ON for NPN.