The MTT MS3003 is a terminal block type millivolt isolator that takes a low-level millivolt signal and converts it into a standard, isolated current or voltage output. It accepts 0~10mV, 0~100mV, ±10mV, or ±100mV DC inputs, with spans from 5mV to 400mV, and a maximum continuous input of 30V DC.
Output is configurable to 4~20mA or 0~20mA current, or 0~10mV, 0~100mV, 0~1V, 0~10V, 0~5V, 1~5V voltage – whatever your PLC or DCS accepts. Zero and span are each adjustable by about ±2.5% of span, with accuracy better than ±0.1% of span at 25°C±5°C and temperature stability better than ±0.2% of span per 10°C change. Response time is 160ms max (0 to 90%).
There is 3-way isolation between input, output, and power, with CMRR of 100dB min (500V AC, 50/60Hz) and insulation resistance of 100MΩ min at 500V DC – this is what keeps ground loops and noise from corrupting a low-level millivolt reading over a long cable run. Dielectric strength is 1500V AC for 1 minute.
Power supply is 24V DC (±10%) or 12V DC (±20%), drawing up to 40mA (24V) or 70mA (12V). The unit mounts on DIN rail with M3.5 screw terminals, in an ABS resin (UL 94V-0) enclosure measuring W25.0 × H94.0 × D40.0mm and weighing under 90g. It is rated for -5 to 55°C operation (5-90% RH non-condensing) and -10 to 60°C storage.
| Input Ranges | 0-10mV DC, 0-100mV DC, ±10mV DC, ±100mV DC (span 5mV to 400mV) |
| Input Resistance | 1MΩ min. |
| Maximum Input Voltage | 30V DC max., continuous |
| Output Signal | 4-20mA, 0-20mA current; 0-10mV, 0-100mV, 0-1V, 0-10V, 0-5V, 1-5V voltage |
| Zero / Span Adjustment | Approx. ±2.5% of span each |
| Accuracy | Better than ±0.1% of span (at 25°C±5°C) |
| Temperature Stability | Better than ±0.2% of span per 10°C change |
| Response Time | 160ms max. (0 to 90%) |
| CMRR | 100dB min. (500V AC, 50/60Hz) |
| Power Supply | 24V DC (±10%) or 12V DC (±20%) |
| Power Consumption | 40mA max. (24V current out), 70mA max. (12V current out) |
| Isolation | 3-way isolation between input, output, and power |
| Insulation Resistance | 100MΩ min. (@ 500V DC) |
| Dielectric Strength | 1500V AC for 1 minute |
| Enclosure / Mounting | ABS resin (UL 94V-0), DIN rail mounting, M3.5 screw terminal |
| Dimensions | W25.0 × H94.0 × D40.0 mm |
| Weight | 90g max. |
| Operating Temperature | -5 to 55°C, 5-90% RH non-condensing |
| Storage Temperature | -10 to 60°C |
Frequently asked questions
What is the MS3003 used for?
It converts low-level millivolt signals, such as those from load cells, strain gauges, or shunt resistors, into a clean, isolated 4 to 20mA or voltage signal that a PLC, DCS, or data logger can read directly.
Can the MS3003 be used with a load cell or strain gauge?
Yes. It accepts millivolt spans as low as 5mV, which covers most load cell and strain gauge outputs, and isolates the signal so ground loops and cable noise don’t affect the reading.
Does the MS3003 need a separate power supply?
Yes, it needs 24V DC or 12V DC to operate — it is not loop-powered. Let us know which supply you have on site so we quote the right version.
Can the MS3003 output a voltage signal instead of 4 to 20mA?
Yes, the output is field-configurable to current or one of several DC voltage ranges, so it can match whatever input your PLC or DCS card accepts.
Download MTT MS3003 Terminal Block Type Millivolt Isolator information here
Datasheet: MTT MS3003 Spec Sheet (PDF)
Manual: MTT MS3000 Series User’s Manual (PDF)
