Hello Everyone,
I am using an MCS-655M Retro-Reflective Sensor that outputs an NPN signal. I am looking to convert this output signal to a 0-10V Analog Signal. My maximum frequency I will see is 200Hz.
My thought was to first use an off the shelf frequency to voltage convertor, but my issue seems to be that the NPN output signal was too low to read. The High/Low were measured and I was getting 730mv High & 350mV Low. So I decided to purchase a LM331 Frequency to Voltage Convertor (This is labeled as a Voltage to Frequency Convertor but can be used in the opposite direction as shown in Figure 18 of the datasheet). I've had to adjust resistor & capacitor values to achieve a Vout of close to 10V @ 200Hz., one thing I realized is the capacitors I purchased are non-polarized so I'm not sure if this has an effect. I am powering the LM331 using 24V, my thought was that the two resistors at pin 7 act as a voltage divider so I adjusted this to divide the voltage down to 500mV in order to sense the low/high change.
I've confirmed with an Oscilloscope that the Frequency Output of the Retro-Reflective Sensor is accurate.
Can you recommend where I may be going wrong or recommend an alternative to convert this output signal to 0-10V analog?
See table at end of post for purchased Components. I've attached my circuit diagram & all related datasheets.
Please let me know if you need any additional information
Thanks!
I am using an MCS-655M Retro-Reflective Sensor that outputs an NPN signal. I am looking to convert this output signal to a 0-10V Analog Signal. My maximum frequency I will see is 200Hz.
My thought was to first use an off the shelf frequency to voltage convertor, but my issue seems to be that the NPN output signal was too low to read. The High/Low were measured and I was getting 730mv High & 350mV Low. So I decided to purchase a LM331 Frequency to Voltage Convertor (This is labeled as a Voltage to Frequency Convertor but can be used in the opposite direction as shown in Figure 18 of the datasheet). I've had to adjust resistor & capacitor values to achieve a Vout of close to 10V @ 200Hz., one thing I realized is the capacitors I purchased are non-polarized so I'm not sure if this has an effect. I am powering the LM331 using 24V, my thought was that the two resistors at pin 7 act as a voltage divider so I adjusted this to divide the voltage down to 500mV in order to sense the low/high change.
I've confirmed with an Oscilloscope that the Frequency Output of the Retro-Reflective Sensor is accurate.
Can you recommend where I may be going wrong or recommend an alternative to convert this output signal to 0-10V analog?
See table at end of post for purchased Components. I've attached my circuit diagram & all related datasheets.
Please let me know if you need any additional information
Thanks!
Item Description | Supplier | Supplier Part No. |
Voltage to Frequency & Frequency to Voltage PREC VLTG-TO-FREQ CONVERTER | Mouser | 926-LM331N/NOPB |
Metal Film Resistors - Through Hole .4watt 2.4Mohms 1% 1/8watt body size | Mouser | 594-5063JD2M400F |
Metal Film Resistors - Through Hole 1/2W 100Kohms 0.5% | Mouser | 71-CMF55100K00DHEB |
Metal Film Resistors - Through Hole 10K ohm 1% 0.4W | Mouser | 756-MFR3-10KFC |
Metal Film Resistors - Through Hole 1KOhm 3/5W 50PPM | Mouser | 279-LR1F1K0 |
Metal Film Resistors - Through Hole .6watt 47Kohms 1% | Mouser | 594-MRS25000C4702FCT |
Multilayer Ceramic Capacitors MLCC - Leaded 50V 1uF X8R 10% RAD LS:2.5mm AECQ200 | Mouser | 810-FA16X8R1H105KRU6 |
Multilayer Ceramic Capacitors MLCC - Leaded 100V 0.010uF 5% AEC-Q200 Radial C0G | Mouser | 810-FA28C0G2A103JRU6 |
Multilayer Ceramic Capacitors MLCC - Leaded 100VDC 470pF 5% CCG AEC-Q200 In Crimp | Mouser | 81-RHS7G2A471J0M2H1A |
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