The MTT MS3761 Slim Plug-In Adder is a two-input signal conditioner that takes two independent DC current or voltage signals and combines them into a single output proportional to their weighted sum. This makes it a practical building block wherever a control system needs a combined reading from two field transmitters, such as summing flow measurements from two lines or blending a process signal with a bias or trim input, without resorting to custom logic in the PLC.
Each input channel has its own configurable scaling factor, so the two signals can be weighted differently before they are summed, giving engineers flexibility to build ratios and blends that suit the specific process. Front-accessible trimmers allow zero and span to be fine-tuned on site, and the module is available with a fast response option for applications where the combined output needs to track changes in either input with minimal delay. As with other members of the MS-series, the MS3761 provides galvanic isolation between its inputs, outputs, and power supply, keeping the summed signal free of noise and ground-loop interference.
| Input Ranges | Current: -100 to 100mA (100µA-200mA span); Voltage: -10 to 10V (200mV-20V span) |
| Input Resistance | 250Ω (4-20mA standard); 1MΩ min. (voltage) |
| Max Allowable Input | 40mA DC (current); 30V DC (voltage) |
| Input Bias | -100 to 100% |
| Output Ranges | Current: 0-20mA; Voltage: -10 to 10V; overall output range 0 to approx. 120% |
| Output Load Limits | Voltage output 2mA max (1V+ span); 4-20mA single output 750Ω max |
| Adjustment | ±5% zero and span via front-accessible trimmers |
| Summing Formula | Output (%) = IN1(%) x K1 + IN2(%) x K2, with K1/K2 configurable 0.1-2.0 |
| Accuracy | Better than ±0.1% of span (at 25°C±5°C); ±0.2% per 10°C temperature effect |
| Response Time | 85ms max (0-90%, step input); optional fast response mode 10ms max |
| CMRR | 100dB min. (500V AC) |
| Isolation | 4-way isolation between input, outputs, power, and ground; 100MΩ min. insulation resistance; 2000V AC dielectric strength (1 minute) |
| Power Supply | 100-240V AC, 24V DC, or 100-240V DC; 4.5-5.5VA max (AC) / 1.4-1.7W max (24V DC) / 4.8-6.0W max (100-240V DC) |
| Dimensions | W29 x H86 x D125mm |
| Weight | 120g (main unit) / 80g (socket) max |
| Terminals | M3.5 screw terminals, 0.8-1.0 Nm torque |
| Mounting | Wall or DIN rail mount |
| Operating Conditions | -5 to 55°C, 5-90% RH non-condensing |
| Storage Temperature | -10 to 60°C |
| Additional Options | Optional fast response mode (10ms max), optional high-load current output |
Frequently Asked Questions
What is the MTT MS3761 used for?
It’s a two-input signal conditioner (adder) that takes two independent DC current or voltage signals and combines them into a single output proportional to their weighted sum. It’s a practical building block wherever a control system needs a combined reading from two field transmitters, such as summing flow measurements from two lines or blending a process signal with a bias or trim input, without custom logic in the PLC.
How does the weighting/summing work?
Each input channel has its own configurable scaling factor (K1 and K2, adjustable from 0.1 to 2.0), so the output equals IN1 times K1 plus IN2 times K2. That lets the two signals be weighted differently before they’re summed, rather than just added 1:1.
What input and output signal types does it accept?
Input accepts current (-100 to 100mA, 100µA-200mA span) or voltage (-10 to 10V, 200mV-20V span), and output is a standard 0-20mA current or -10 to 10V voltage span. Tell us your two input signal types and we can confirm the setup.
Can I fine-tune the zero and span after installation?
Yes, front-accessible trimmers give ±5% zero and span adjustment, so the combined output can be matched exactly to what the receiving instrument expects on site.
How do I know if the MS3761 is right for my application?
If you need to combine two DC signals into one output, whether that’s summing two flow readings or adding a trim/bias signal to a process value, the MS3761 handles that without extra PLC logic. Send us both input signal types and the weighting you need and we can confirm before you order.
Download MTT MS3761 Slim Plug-In Adder information here
Spec Sheet: MTT_SpecSheet1_MS3761_Rev270_E
Manual: MTT_Manual1_MS3761_Rev140_E
