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Honeywell, Inc. Honeywell reserves the right to make changes to improve reliability, function or design. Honeywell does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license...
IPT is a proven Honeywell silicon piezo-resistive pressure sensor with both pressure and temperature sensitive elements. The IPT is both small and lightweight and can be easily integrated into a wide variety of applications that require high performance in a small package.
Not including any mounting hardware. Dimensions in section 2.3 do not include Humiseal 1A33 conformal coating which is typically applied to the PWB assembly at a thickness of 1-3 mils. Operation with a digital interface > 3.3V can damage the IPT and cause shifts in the ADC output. IPT electronics require protection from humidity.
AD7799. The temperature channel uses a 16-bit ADC from Analog Devices, P/N AD7790. After applying power to the IPT and before obtaining data, each data channel needs to be initialized. As per the manufacturer’s data sheets, the SPI serial clock for each ADC should be ≤ 5 MHz. During reads and writes to the ADC’s as detailed below, the appropriate chip-select line must be brought low...
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3.1.1.1.5 Reading Note: after initialization is complete, reading the Configuration and Mode Registers is recommended to ensure they have been set as desired. See the AD7799 manufacturer’s datasheet for information regarding reads of the Configuration and Mode registers. 3.1.1.2 Temperature Channel The temperature channel ADC is controlled and configured via a number of on-chip registers.
3.1.2 Normal Operation (Polling) 3.1.2.1 Pressure Channel After initializing the Mode register per section 3.1.1.2, a new 24-bit pressure value will be available in ~ 5.26 ms (1 ms settle time + 4.26 ms conversion). The pressure conversion remains in the data register and DOUT/ RDY remains active (low) until the data is read or another conversion is performed.
3.1.3 Other Modes The Honeywell IPT has been tested using the “Initialization” and “Normal Polling” as described in sections 3.1.1 and 3.1.2. above. Both pressure and temperature channel ADCs may also be configured to operate in Continuous Conversion and Continuous Reads modes. Performance should be substantially the same in these...
IPT EEPROM contents.) Coefficients (A, a1, a2, etc.) for the identified algorithm are stored in the IPT EEPROM. The algorithm result (Y) is a corrected pressure reading in pounds per square inch (PSI). ADC values from the temperature channel (normalized) are used to correct the readings for thermal effects.
3.2.1.2 Algorithm #2 Differences from Algorithm #1 are highlighted in blue Y = A + (F1 × p) + (F2 × p ) + (F3 × p ) + (F4 × p ) + (F5 × p Where: F1 = a1 + (b1 × t) + (c1 × t ) + (d1 ×...
Starting in the May 2011 timeframe, coefficients for converting 16-bit Pressure Sensor Temperature values to °C have been appended to the EEPROM contents of new IPT transducers. This supplemental information allows users, if desired, to separately monitor the temperature of the pressure sensor. The...
00 through 93. Example: -7.2467064 = C0E7E504 3.3.2.2 Full Scale Pressure Range The IPT full scale pressure range (FS) is stored in 32-bit IEEE 754 format in locations 94 through 97. Example: 20 = 41A00000 3.3.2.3 Minimum/Maximum Operating/Storage Temperature Limits IPT operating/storage temperature limits (Min/Max Op/Stor Temp) are stored as 8- bit signed integers in locations 98 through 9B.
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Note: These values can be used to determine if the IPT is being used within its specified operating range. If samples from the pressure ADC are outside this range, the accuracy of the correction algorithm cannot be guaranteed. 3.3.2.6 Minimum/Maximum Temperature Output...
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3.2.1, a transducer-specific 24-bit Seed Pressure Count (spc), a 16-bit Seed Temperature Count (stc) and the corresponding 32-bit IEEE 754 Corrected Seed Pressure reading (csp) have been stored in the IPT EEPROM: The 24-bit spc value is stored in locations C8 through CB with leading zero’s.
4 Installation Recommendations 1. IPT media compatibility is non-condensing, non-corrosive, non-combustible gases. To ensure the best transducer performance it is strongly suggested that IPT transducers and associated plumbing be oriented to prevent accumulation of debris or condensation in the pressure ports.
2. Minimize mechanical stress between the circuit board and the on-board pressure sensor. 5 Marking An adhesive label on the O.D. of the IPT sensor contains the unit’s model code, serial number, and date code (MMDDYY). IPT0020A33R-T003 S/N 2376 081710...
6 Fletcher Checksum 6.1 Calculation The Fletcher checksum calculation results in two sums: SUM1[R-1] = D[0] + D[1] + …D[R-1] SUM2[R-1] = SUM1[0] + SUM1[1] + …SUM1[R-1] where R = number of bytes in the EEPROM storage area from 00 through B5 (182d), including the check bytes, and where all additions are modulo 256.
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Customer Service Email: quotes@honeywell.com www.pressuresensing.com No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, for any purpose, without the express written permission of Honeywell, Inc.
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Honeywell reserves the right to make changes to improve reliability, function or design. Honeywell does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.