The MTT MS3781 Slim Plug-In Accumulator converts a continuous DC current or voltage signal, such as a flow rate reading, into a pulse train whose rate corresponds to the input, giving totalizers, counters, and batch controllers a pulse signal they can accumulate into a running total. This turns an analog rate measurement into the pulse format that legacy counting instrumentation and PLC high-speed counter inputs are typically built to accept.
Two independent outputs are provided: a TTL-level or open-collector pulse output for driving electronic counters and PLC inputs, and a Form A relay contact output for interfacing with electromechanical counters or other equipment that needs a dry contact pulse. The accumulation rate is configurable to match the process, and galvanic isolation between input, output, and power keeps the pulse signal free of noise and ground-loop interference as it feeds downstream totalizing equipment.
| Voltage Input | 0-10V DC (configurable); 1MΩ min. resistance; 200mV-20V span |
| Current Input | 4-20mA standard (250Ω); 100µA-200mA range available |
| Max Input | 30V DC (voltage model); 40mA DC (current model) |
| Output 1 | TTL level or open collector, 40V DC / 50mA max |
| Output 2 | Relay contact (Form A); 125V AC/0.5A or 30V DC/2A (resistive load) |
| Pulse Width | 125ms ±20% |
| Accumulation Rate | 10-9990 p/h standard; 1-999 p/h optional |
| Accuracy | Better than ±0.5% of span (at 25°C±5°C); ±0.2% per 10°C temperature drift |
| Response Time | 50ms + pulse interval max |
| Dropout Level | 0-20% (configurable) |
| Isolation | Galvanic isolation between input, output, and power; 100MΩ min. insulation resistance @500V DC; 2000V AC dielectric strength for 1 minute (input/output) |
| Power Supply | 100-240V AC, 24V DC, or 100-240V DC; 5.0VA max (AC) / 1.5W max (24V DC) / 2.5W max (DC) |
| Dimensions | W29 x H86 x D125mm |
| Weight | 120g (main unit) / 80g (socket) |
| 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 |
Frequently Asked Questions
What is the MTT MS3781 used for?
It converts a continuous DC current or voltage signal, such as a flow rate reading, into a pulse train that totalizers, counters, and batch controllers can accumulate into a running total. This bridges an analog rate measurement to equipment that expects a pulse-count input.
What input signals does it accept?
Voltage input of 0-10V DC (configurable, 200mV-20V span) or current input of 4-20mA DC (100µA-200mA range available). Tell us your transmitter’s output signal and we can confirm which input configuration you need.
What output options are available?
Two independent outputs: a TTL-level or open-collector pulse output (40V DC / 50mA max) for electronic counters and PLC high-speed counter inputs, and a Form A relay contact output for electromechanical counters or other dry-contact equipment.
Can the accumulation rate be adjusted to match my process?
Yes. Standard units cover 10-9990 pulses per hour, with a 1-999 pulses per hour option available, so the pulse rate can be matched to the counting equipment downstream rather than left fixed.
How do I know if the MS3781 is right for my application?
If you have a continuous analog rate signal, such as flow, and need to feed it into a pulse-counting totalizer or PLC counter input, the MS3781 handles that conversion with isolated pulse and relay outputs. Send us your input signal type and the accumulation rate you need and we’ll confirm before you order.
Download MTT MS3781 Slim Plug-In Accumulator information here
Datasheet: MTT_SpecSheet1_MS3781_Rev130_E
