The MTT MS3725 is a slim plug-in high/low signal selector that compares two DC input signals and passes through whichever is higher or lower, converting the selected value into a standard, isolated output. It is a natural fit for redundant sensor setups, where a control system needs a single reliable reading drawn automatically from two independent transmitters, whether that means picking the higher of two pressure readings or the lower of two temperature readings for a safety interlock.
Selection sensitivity is tight enough to catch even small differences between the two inputs, and an optional fast-response version cuts the reaction time down to 10ms for applications that need a quicker switch-over. Like the rest of the plug-in transmitter series, the MS3725 clips into its own socket base for fast swap-out during calibration or maintenance without disturbing the field wiring, and flexible AC or DC power plus wall or DIN rail mounting make it easy to fit into an existing panel.
| Input (Current) | 0-20mA to 10-50mA, within 0-100mA range |
| Input (Voltage) | 0-1V to 1-5V, within 0-10V range |
| Input Resistance | 10Ω to 250Ω, depending on signal type |
| Max Continuous Input | 40mA DC or 30V DC |
| Output | 4-20mA current or 10mV to ±10V voltage; single or dual isolated output |
| Output Load | 750Ω max. (4-20mA single); 550Ω/350Ω max. (dual) |
| Adjustments | ±5% zero and span |
| Selection Sensitivity | Better than 0.5% of span |
| Accuracy | Better than ±0.1% of span (at 25°C±5°C) |
| Response Time | 85ms max. (0-90%); 10ms max. with fast-response option |
| Temperature Effect | ±0.2% of span per 10°C change |
| CMRR | 100dB min. |
| Isolation | 4-way isolation between input, output, power, and ground |
| Insulation Resistance | 100MΩ min. |
| Dielectric Strength | 2000V AC for 1 minute |
| Power Supply | 100-240V AC (47-63Hz), 24V DC (±10%), or 100-240V DC |
| Power Consumption | 4.5-5.5VA max. (AC), 1.4-1.7W max. (DC) |
| Dimensions | W29 × H86 × D125mm |
| Weight | 120g max. (main unit), plus 80g max. socket |
| Mounting | Wall or DIN rail mounting |
| Terminals | M3.5 screw terminals |
| Operating Temperature | -5 to 55°C |
| Operating Humidity | 5 to 90% RH, non-condensing |
Frequently Asked Questions
What is the MTT MS3725 used for?
It compares two DC input signals and passes through whichever one is higher or lower (selectable), converting the chosen value into a standard, isolated output. It’s a common way to build a single reliable reading from two redundant sensors, such as selecting the higher of two pressure readings or the lower of two temperature readings for a safety interlock.
Can I choose whether it selects the higher or lower signal?
Yes — the selection mode (high-select or low-select) is set to your requirement. Tell us which comparison your application needs and we can confirm it’s set correctly.
How sensitive is the selection between the two inputs?
The selection sensitivity is better than 0.5% of span, so it reliably picks the correct signal even when the two inputs are close together.
Is there a faster-responding version of the MS3725?
Yes — an optional fast-response version cuts the reaction time down to 10ms for applications where the selector needs to switch over quickly.
How do I know if the MS3725 is right for my application?
If you have two redundant sensors and need a single output that’s automatically the higher or lower of the two, the MS3725 is built for that. Send us your input signal ranges and which comparison you need and we can confirm before you order.
Download MTT MS3725 Slim Plug-In High/Low Signal Selector information here
Spec Sheet: SpecSheet1_MS3725_Rev300_E.pdf
Manual: Manual1_MS3725_Rev160_E.pdf
