The MTT MS3954 Chassis-mounting High-Level Signal Conditioner takes a standard current or voltage process signal and re-issues it as a clean, galvanically isolated 4-20mA current loop, letting engineers break ground loops and interference between a transmitter and the PLC, DCS, or recorder reading it. Because the output is a current loop rather than a voltage signal, it can drive longer wiring runs to the receiving instrument without the accuracy loss that plagues voltage transmission over distance.
Built in the compact chassis-mount format shared with the rest of the MS39-series for high-density installations on MTT’s RC3900 chassis platform, the MS3954 accepts 4-20mA, 1-5V, or 0-2V DC inputs and includes an open-collector wire-break alarm output that flags a broken signal loop before it causes a silent process upset. Front-accessible trimmers allow zero and span adjustment, and isolation between input, output, and power supply keeps the reissued signal free of noise and ground-loop interference.
| Input Signal | 4-20mA DC, 1-5V DC, or 0-2V DC |
| Input Resistance | 1MΩ min. (voltage input); 250Ω (current input) |
| Max Allowable Input | 30V DC (voltage); 40mA DC continuous (current) |
| Output Signal | 4-20mA DC |
| Output Load | 550Ω max |
| Wire Open Detection | Open-collector alarm output, ~10% F.S. detection level |
| Adjustment | ±2% of span, zero and span, via front trimmer |
| Accuracy | ±0.1% F.S. (25°C±5°C); ±0.2% span per 10°C temperature effect |
| Power Sensitivity | ±0.1% of span max. at 10% variance |
| Response Time | 15ms max (0-90% step); adjustable options down to 2ms or up to 200Hz on consultation |
| CMRR | 100dB min. (500V AC, 50/60Hz) |
| Isolation | Mutual isolation across input, output, and power; 100MΩ min. insulation resistance; 500V AC dielectric strength (input/power), 1500V AC (output/other) |
| Surge Withstand | Per ANSI/IEEE C37.90.1-1989 |
| Power Supply | 24V DC ±10%, 45mA max; 300mA fuse standard |
| Dimensions | W19.5 x H53 x D84mm |
| Weight | Approx. 70g |
| Housing | ABS resin (UL94V-0); glass-fabric epoxy PCB (CEM-3) |
| Mounting | Chassis mount, RC3900-□□AO base required |
| Operating Conditions | 0-55°C, 90% RH max non-condensing |
| Storage Temperature | -10 to 60°C |
| Additional Features | Anti-humidity PCB coating (HumiSeal 1A27NS); self pop-up wiring screws |
Frequently Asked Questions
What is the MTT MS3954 used for?
It takes a standard current or voltage process signal and re-issues it as a clean, galvanically isolated 4-20mA current loop, letting you break ground loops and interference between a transmitter and the PLC, DCS, or recorder reading it.
What input signals does it accept?
4-20mA, 1-5V, or 0-2V DC. Tell us your transmitter’s output signal and we can confirm compatibility.
Why re-issue the signal as a 4-20mA current loop?
A current loop can drive longer wiring runs to the receiving instrument without the accuracy loss that affects voltage signals transmitted over distance, making it the standard choice for feeding a signal to equipment some distance away.
Does it detect a broken signal wire?
Yes, an open-collector wire-break alarm output flags a broken signal loop before it causes a silent process upset, so a wiring fault is caught rather than mistaken for a real low reading.
How do I know if the MS3954 is right for my application?
If you need to isolate and re-issue a process signal as a clean 4-20mA loop, with wire-break detection, the MS3954 on an RC3900 base covers that. Send us your input signal type and we’ll confirm before you order.
Download MTT MS3954 Chassis-mounting High-level Signal Conditioner for Output Isolation information here
Datasheet: MTT_MS3954_Datasheet
