Validyne DR800 Draft Range Transmitter is designed exclusively for very low pressure measurement needs. It has a “true” full-scale range as low as ±0.25” H2O, making it ideal for air flow control applications. It can be turned down to ±0.1” H2O; higher full-scale ranges to ±100” H2O are available. The DR800 offers 0.5% accuracy and an operating temperature range of -20°F to +185°F. The total combined temperature effects are less than 3%/100°F and it also has simplified the zero and span adjustments.
The Model DR800 uses a programmable circuit board jumper in conjunction with a 20-turn potentiometer to achieve a smooth, accurate zero adjustment. Using the pot/jumper combination, ranges can be selected from –100% zero elevation to +85% zero suppression (see Fig. 1). Also, the span adjust has a HI and LO gain jumper to allow better full-scale setpoint resolution. This achieves more turns from the potentiometer over a smaller percentage of the span and zero adjust range making critical setpoint calibrations easier and less time consuming.