DR800 draft range transmitter

The Validyne Model 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.

Validyne 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 set-point resolution. This achieves more turns from the potentiometer over a smaller percentage of the span and zero adjust range making critical set-point calibrations easier and less time consuming.

The DR800 has been designed for easy field repair if required. All the electronics are housed in the NEMA housing on top of the transducer and joined to the transducer through a single plug in the neck of the transmitter. The entire electronics housing can be removed and replaced in a matter of minutes without removing the transducer from its mounting. The electronic circuit board is also field repairable; no special tools are required.