Voltage Output to Low Impedance E/P Transducer
Voltage Output to Low Impedance E/P Transducer
(OP)
I have many old E/P transducer that requires1-5VDC inputs. My PLC voltage output card can supply 1-5VDC, but requires a load impedance of at least 1kohm. The E/P transducer's input impedance is only 333 Ohms. Does anyone have a recommended solution to this problem? (short of replacing the E/P's?)





RE: Voltage Output to Low Impedance E/P Transducer
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Voltage Output to Low Impedance E/P Transducer
Does your PLC card also put out 4-20 mA? If so the solution is simple, put a 1K resistor in parallel with your 333 Ohm transducer to make the combined 250 Ohm. Your transducers are now 4-20Ma
Regards
Roy
RE: Voltage Output to Low Impedance E/P Transducer
RE: Voltage Output to Low Impedance E/P Transducer
The resistors will have to go at the instrument otherwise the resistance of the cables will have to be taken in to account. You would end up with some odd combination like (e.g.) 341Ω combined instrument and cable resistance paralleled with 937Ω at the PLC. If you can open the instrument up solder them internally across the terminals so they don't get lost.
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