The MTT MS3908 Chassis-mounting Frequency/Analog Converter takes a pulse train from a dry contact, voltage pulse, or current pulse source and converts it into an isolated DC output proportional to the pulse frequency, giving panels a way to turn a raw frequency signal from a flow meter, tachometer, or speed sensor into a standard analog reading. Packaged in the compact chassis-mount format shared with the rest of the MS39-series, it is built for high-density installations on MTT’s RC3900 chassis platform.
The input frequency range is user-selectable from as low as 0-20Hz up to 0-20kHz, letting one converter cover a wide variety of pulse-generating instruments simply by configuring the range rather than substituting a different model. Dual output combinations of voltage and current are available to match the receiving equipment, front-accessible trimmers allow zero and span adjustment, and isolation across all ports keeps the converted signal free of noise and ground loops as it feeds downstream instrumentation.
| Input Signal Types | Dry contact, AC voltage pulse (0.1-100Vp-p), DC voltage pulse, 4-20mA, or custom current pulses |
| Frequency Range | 0-20Hz to 0-20kHz (user-selectable) |
| Input Resistance | 1MΩ min. (voltage); 250Ω (current) |
| Max Input | 30V DC continuous (voltage); 40mA DC continuous (current) |
| Pulse Width | 20µs min. |
| Duty Ratio | 40-60% |
| Output Options | 1-5V, 0-5V, 0-10V, ±5V, ±10V DC, or 1-5V/4-20mA combinations |
| Output Load | 2mA max (voltage); 300Ω max (current) |
| Adjustment | ±2% of span, zero and span, via front trimmer |
| Accuracy | ±0.3% F.S. (25°C±5°C), including 0.2% ripple; ±0.2% per 10°C temperature effect |
| Response Time | 8s @20Hz to 500ms @20kHz |
| CMRR | 100dB min. |
| Isolation | Isolation across all ports; 100MΩ min. insulation resistance; 1500V AC dielectric strength (input to others), 500V AC (outputs/power) |
| Power Supply | 24V DC ±10%, 55mA max; 300mA fuse standard |
| Dimensions | W19.5 x H53 x D84mm |
| Weight | Approx. 70g |
| Mounting | Chassis mount, RC3900 base required |
| Operating Conditions | 0-55°C, 90% RH max non-condensing |
| Storage Temperature | -10 to 60°C |
| Additional Features | Anti-humidity coating; pop-up wiring screws; multiple density installation options |
Frequently Asked Questions
What is the MTT MS3908 used for?
It takes a pulse train from a dry contact, voltage pulse, or current pulse source and converts it into an isolated DC output proportional to the pulse frequency, turning a raw frequency signal from a flow meter, tachometer, or speed sensor into a standard analog reading.
What input frequency range does it cover?
User-selectable from as low as 0-20Hz up to 0-20kHz, so one converter can cover a wide variety of pulse-generating instruments by configuring the range rather than substituting a different model. Tell us your source’s pulse frequency range and we can confirm the configuration.
What input signal types does it accept?
Dry contact, voltage pulse, or current pulse sources. Tell us what type of pulse your instrument outputs and we can confirm compatibility.
What output options are available?
Dual output combinations of voltage and current are available to match the receiving equipment, with isolation across all ports keeping the converted signal free of noise and ground loops.
How do I know if the MS3908 is right for my application?
If you have a pulse or frequency output from a flow meter, tachometer, or speed sensor and need a standard analog signal instead, the MS3908 on an RC3900 base handles that conversion. Send us your source’s pulse type and frequency range and we’ll confirm before you order.
Download MTT MS3908 Chassis-mounting Frequency/Analog Converter information here
Datasheet: MTT_MS3908_Datasheet
