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Panel meter





The panel meter 2251 is designed for two pulse sensors such as NPN-, PNP-, Namur -sensors, closing contact or pickup. The meter calculates the difference between the input frequencies, subtraction A-B, or alternatively, the meter divides the input frequencies, division A/B.

The input frequency range 0,0001Hz..5 kHz is exceptionally wide starting with very low frequencies. The display is scaleable on the whole frequency range, e.g. 0-1,23 Hz can correspond to the range 0-5000 on the display. Output is freely scaleable on the basis of the display, e.g. 4-20 mA. Two different measuring methods are applied: in low frequencies the time interval between two incoming pulses is measured and in higher frequencies the frequency.

Load manuals (pdf)
Load datasheets (pdf)
Load technical drawings

Input details


Namur, Pickup, PNP, pulse sensors, closing contact

input channels



0.01% full scale

sensor supply

24 VDC, max. 150 mA

Display details

display color


number of digits


indicator lights

alarm levels 1 and 2


7-segment LED

digit size

14.5 mm

Power supply

current consumption

24 VDC: 70...110 mA depending on the digit count

supply voltage

24 VDC: 12...32 VDC / 24 VAC, 230 VAC: 85-260 V AC/DC

Inputs: Scalable difference display (speed) for two pulse sensors (pulse/sec.) Outputs: 0/4-20 mA, 0-5/10V, serial RS485/232, 2 alarm relays