The DataWatch^(TM) (DW) is a low-cost, 16-bit C/C++ programmable industrial controller based on the NEC V25 processor. The DW supports up to 512 KB ROM/Flash, 512 KB battery-backed SRAM, a 512-byte EEPROM, a real-time clock (RTC72421), up to three serial ports, three 16-bit timers/counters, TTL I/O lines, 14 solenoid drivers, power failure reset, watchdog, and 24x4 field-removable screw terminals. 12-bit ADC, DAC, and a 16x2 character LCD interface are also available.

The DW is designed for industrial and field applications that demand mobility. The 96 (24x4) optional field-removable screw terminals of the DW allow a unit to be placed and removed without disconnecting individual wires, which relieves the constant hassle of swapping, moving, and upgrading a system. This feature saves time and minimizes disastrous cross-wiring. The factory default configuration provides fixed terminals, if the optional field-removable terminals are not needed.

At the 24x4 screw terminals, the DW provides 16 TTL inputs, 8 comparator inputs, 14 solenoid drivers, and 8 bi-directional TTL I/Os with LED indicators.

The 16 TTL inputs are buffered by two PALs and can be configured as multiplexed events counter inputs, external interrupt inputs or digital inputs. An on-board PPI (82C55) drives 14 solenoid drivers and 8 bi-directional TTL I/Os. Eight resistor-protected comparators can be used to measure either digital or analog inputs (0 to 10V) in 16 levels.

An optional 11 resistor-protected 12-bit ADC inputs and four 12-bit DAC outputs can be installed on the DW. The ADC (TLC2543) features reference inputs (2.5V or 5V), a sample rate of up to 2.5 kHz, and a 0-10V input voltage range. The DAC (MAX537) outputs 0V to 2.5V, with a typical slew rate of 3V/s with a 5 kW load. The DAC is installed with a 2.5V precision reference (20 ppm/° C, LT1009).

The 14 solenoid drivers can sink up to 350 mA each at 50V.

Two RS-232 serial ports support up to 115,200 baud. One optional UART (SCC2691) supports 8-bit/9-bit RS-485 networking. Two standby modes, HALT and STOP, can reduce power consumption. A 16-pin LCD interface header supports various types of LCDs.