We had an enquiry from a customer whose existing 4-20mA transmitter needed to feed both a PLC and a separate SCADA system, but wiring both loads onto the same loop was causing accuracy problems — the extra load resistance was pulling the loop out of its working range, and grounding both systems to the same signal was introducing noise.
This kind of problem shows up whenever a single DC current or voltage signal needs to go to more than one place, or needs its range changed — say converting a 0-10V panel output into a 4-20mA signal a PLC input card actually accepts. Simply splicing a second load onto an existing loop adds resistance and risks dragging the signal down or introducing a ground loop between the two receiving systems. What’s needed is something that reads the original signal cleanly and re-transmits it as one or two properly isolated outputs.
For this, we would normally recommend the MTT MS3704, a slim plug-in high-level signal conditioner. It accepts a wide range of DC current inputs (100μA to 200mA) or DC voltage inputs (200mV to 600V), covering common ranges like 4-20mA, 0-20mA, 0-10V, and ±10V, and converts them into a clean 0-20mA or 10mV-20V DC output — available as a single output or isolated dual output. The dual-output version keeps Output 1 and Output 2 fully isolated from each other, the input, and the power supply, so one signal can safely feed two separate systems without interference. Like the rest of the plug-in range, it mounts on its own DIN-rail socket base for fast swap-out, and an optional /K fast-response version brings the response time down to 10ms for control loops that need it.
Before we quote, we would normally check:
- Exact input signal type and range (current or voltage)
- Whether you need a single output or isolated dual output
- Output signal range required
- Power supply available at the panel (AC or DC)
- Whether you need standard or fast (/K) response time
Hope this helps — send us your input signal and the output you need, and we can confirm the right model.
| Input Types | DC current (100μA to 200mA) or DC voltage (200mV to 600V); common ranges include 4-20mA, 0-20mA, 0-10V, 4-10V, ±5V, ±10V |
| Input Resistance | 10Ω to 1MΩ depending on signal type |
| Allowable Input | 30V DC max. continuous (voltage inputs); 40mA DC max. continuous (current inputs) |
| Output | 0-20mA DC current or 10mV-20V DC voltage (single or isolated dual output) |
| Output Load (4-20mA) | 750Ω max single output; 550Ω/350Ω max for dual outputs |
| Isolation | 4-way isolation between input, Output 1, Output 2, power, and ground |
| Power Supply | 100-240V AC, 24V DC, or 100-240V DC (4.0VA max single, 5.0VA max dual at 100-240V AC) |
| Accuracy | Better than ±0.1% of span (at 25°C±5°C) |
| Response Time | 85ms maximum (0-90%); 10ms with /K fast-response option |
| Temperature Effect | Better than ±0.2% of span per 10°C change |
| CMRR | Minimum 100dB |
| Insulation Resistance | 100MΩ minimum at 500V DC |
| Dielectric Strength | 2000V AC for one minute |
| Dimensions (W x H x D) | 29mm x 86mm x 125mm |
| Weight | Main unit up to 120g; socket up to 80g |
| Mounting | Wall or DIN rail mounting, plug-in socket base |
| Terminals | M3.5 screw terminals |
| Operating Temperature | -5 to 55°C ambient |
| Operating Humidity | 5-90% RH, non-condensing |
Frequently Asked Questions
What is the MTT MS3704 used for?
It reads an existing DC current or voltage signal (like 4-20mA or 0-10V) and re-transmits it as a clean, isolated output — useful for feeding a second system, re-ranging a signal, or breaking a ground loop.
Can the MS3704 convert between different signal ranges, like 0-10V to 4-20mA?
Yes — within its accepted input and output ranges, the MS3704 can re-range a signal as well as isolate it. Tell us your source signal and the range your receiving equipment needs.
What’s the difference between the MS3704 and the MS3704 variants (MS3704-D1, MS3704-S, MS3704HI, MS3704IS, etc.)?
These are variants within the MS3704 family with different input ranges, isolation configurations, or accuracy specs. If you’re replacing an existing unit, check the exact model code on the old unit’s label, or send us your input/output requirements and we’ll confirm the right variant.
Is a fast-response version available?
Yes — the standard MS3704 responds in 85ms, and a /K fast-response option brings that down to 10ms for control loops that need a quicker reaction.
How do I know which MS3704 model I need?
Send us your input signal type and range, whether you need a single output or isolated dual output, and the output signal your PLC or DCS expects. We’ll confirm the right model before you order.
Download MTT MS3704 Slim Plug-In High-Level Signal Conditioner information here
Spec Sheet: MTT MS3704 Spec Sheet
Manual: MTT MS3704 Manual
