Micro-processor Based Digital Differential Pressure Switch 微型處理器,數(shù)字差壓開關(guān) Advantages General Description Micro-processor based digital differential pressure switch/transmitter for industrial applications Adjustable switch points allow the user to obtain various pressure settings for each of the 2 switches and span Measuring ranges from 0.1 to 35kgf/cm2 Advanced piezoresistive silicon measuring cell Excellent accuracy and long term stability 4 digit LED local display 2 switching points with analog output signal Measuring range turn down maximum 10 : 1 Applications The high precision micro-processor based digital differential pressure switch with analog output signal can be used for a wide range of applications in process control, automatic machinery and hydraulic or pneumatic system design. Chemical, petrochemical, food and drug process controls Hydraulic and pneumatic equipments Machine tools and automatic machinery LPG and LNG transmission control and storage tank monitoring Engine monitoring and control Vacuum pump and injection molding machine Powered DC or AC(optional) P929 series micro-processor based digital differential pressure switch uses two matched piezoresistive silicon measuring chips, offering high stability and performance with true wet/wet operation, suitable for measuring differential pressure of gases and liquids compatible with stainless steel. The 929, with its built-in piezoresistive pressure measuring chip, a 4-digit digital display, 2 switching points, 4~20mA analog output signal and a front function keys, offers the user all the advantages of a modern electronic pressure measurement. External adjustments allow the user to set the pressure ranges, switch points, deadband and zero or span calibration, etc. It has a water resistant, explosion-proofed for complete protection from harsh environment and its 4~20mA current output is ideal for remote monitoring of both primary and secondary process variables. It is extremely versatile and suitable for measuring dynamic and static pressure. The pressure to be measured acts through thin corrosion resistant stainless steel 316L diaphragm on a silicon measuring element. The pressure transmitting medium is silicon oil. The measuring element contains diffused piezoresistive resistors which are connected into a Wheatstone bridge. The output signal of this bridge is temperature compensated and converted into a standardized current or voltage output signal. Technology Piezoresistive silicon pressure sensor Pressure ranges 0~0.1 to 35kgf/cm2 Pressure reference Differential pressure Overload 3 ×full scale without damage Output Signal 2 switching points 4~20mA current output 2 switching points with analog output (4~20mA) Other signals available on request Local display LED 4 digit Electrical connection type Terminal head with Ex-protection Excitation voltage 24V DC or 85~260V AC (option) Load resistance max@24V 500Ω at 24V Influence of excitation 0.01% FSO/V Power ripple ≤500mV P-P Reverse polarity Protected Shock resistance No change in performance after 10Gs for 11ms Vibration 0.1G (1 m/s/s) maximum Response time(10~90%) ≤2 milliseconds Switching current Maximum 1.2A Range turn down Maximum 10 : 1 Accuracy ≤±0.3% FSO Non-linearity ±0.99% FSO typical Repeatability ±0.015% FSO typical Pressure hysteresis ±0.010% FSO typical Long term stability ±0.3% FSO over 6 month Cutoff frequency(-3 d B) ≤2kHz Reference temperature 35°C Operating temperature range -40~125°C Compensated temperature range 0~82°C Thermal sensitivity shift ≤±0.2%FSO in reference to 35°C typical Thermal zero shift ≤±0.2% FSO in reference to 35°C typical Thermal hysteresis ≤±0.1% FSO in reference to 35°C typical Process connection PT1/4″female thread(standard) Other connections available on request Electrical connection PT1/2″female Process media Gases and liquids compatible with stainless steel 316 Materials wetted by process Diaphragm : Stainless steel 316L Housing : Aluminum die-casting terminal head Gasket O-ring : Viton (HNBR, CSM, etc.) Enclosure rating IP65 Explosion protection Ex d IIC T6 Influence of mounting position Not critical. Weight Approx. 1700g Options Mounting bracket Remote sealed diaphragm Note : ① If it is installed in explosive atomosphere, the covers should be kept tight when circuit alive. |