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INW - PT2X Instruction Manual
Register addresses for PT2X
Addresses for PT2Xs with fi rmware lower than 2.0
Zero Based
One Based
Pressure 62592
62593
Temperature 62594 62595
Addresses for PT2Xs with fi rmware 2.0 or higher
Zero Based
One Based
Temperature 62592 62593
Pressure 62594
62595
Measurement Timing
When you request a reading via Modbus, the sensor wakes up, returns the current
values in the registers, and then starts taking new readings and updating the registers.
After approximately 10 seconds, if no more readings have been requested, the sensor
goes back to sleep.
Because of this, the fi rst reading you get will be old. If you are taking readings at
intervals of less than 10 seconds, simply ignore the fi rst reading — all remaining
readings will be current. On the other hand, if you are taking readings at intervals of
greater than 10 seconds, take a reading, ignore it, wait one second, take another reading.
Record this second reading.
Data Format
The data is returned as 32-bit IEEE fl oating-point values, highword fi rst, also referred
to as big-endian or fl oat inverse.
For further information and detailed Modbus examples, see INW application note,
“
Modbus Direct Read on AquiStar Smart Sensors
” available from our web site at http://
www.inwusa.com/appnotes.htm.