The Mitsubishi FX3U-64MT/DSS is a MELSEC-F Series main unit with 32 DC 24 V inputs and 32 transistor source outputs, running a 64K-step program in RAM. RS-422 is built in; USB is optional. The unit accepts expansion modules up to 256 local I/O points and 384 combined local plus remote.

Mitsubishi FX3U-64MT/DSS PLC, 64K steps, source output
Mitsubishi MELSEC-F Series FX3U base unit, DC 24 V, 32 inputs, 32 transistor source outputs, 64K steps program memory, expandable.
Specifications
| Parameter | Value |
|---|---|
| Series | MELSEC-F SERIES |
| Parameter | Value |
|---|---|
| Expandable | YES |
| Parameter | Value |
|---|---|
| Weight | 1 kg |
Product details
Frequently asked questions
What is the USB option on this unit?
USB is listed as an option, meaning it is not included on the base unit but can be added via an optional module.
What type is the FX3U-64MT/DSS?
The type is FX3U within the MELSEC-F series.
Will the FX3U-64MT/DSS drop into a panel wired for FX5U-80MT/ESS?
No. The FX3U operates on 24 VDC, while the FX5U requires 100–240 VAC. I/O counts and wiring differ, so a direct swap is not possible without panel modifications.