The MD890 series GPS digital clock manual explains features, installation, interface connections, time and timezone settings, and computer synchronization.
The MD890 series GPS digital clocks from Mengdí Electronics provide high‑accuracy time using GPS as the primary source. Models are available in 1U, 2U, 5‑inch and 8‑inch displays, with master clocks containing a GPS receiver and slave clocks receiving time via RS485.
The manual details front and rear panel functions, antenna installation, brightness adjustment, time and timezone configuration, 1PPS output, serial communication parameters, and how to use the supplied GPS_TIME.EXE program to synchronize a computer with the clock. This manual is written in Chinese.
| Display sizes | 1U, 2U, 5‑inch, 8‑inch |
|---|---|
| Time accuracy | up to 12 µs |
| Maximum slave clocks per master | 32 |
| Maximum RS485 cable distance | 1200 m |
| Display brightness levels | 16 |
| RS232 baud rate | 9600 baud |
| RS232 data format | AA+hh+mm+ss+YY+MM+DD+satellite+XOR+55 |
A single master clock can drive up to 32 slave clocks, with a cable distance of up to 1200 meters; additional slaves or longer distances can be expanded if needed.
Use the + or – button; each press changes the brightness by one level, with a total of 16 adjustable levels that are remembered after power loss.