Model H-3521 Liquid & Gas Compatible Pressure Sensor with SDI-12, 4-20mA and Modbus Outputs Owner's Manual Version 1.5 D E S I G N 75 West 100 South, Logan, Utah 84321 A N A L Y S I S Phone: (435) 753-2212 A S S O C I A T E S , Fax: (435) 753-7669 I N C. Web: http://www.waterlog.com E-mail: waterlog@waterlog.
User Agreement/ WATERLOG® Warranty 1. NATURE OF THE PRODUCT This agreement accompanies a pressure measuring system comprising firmware, circuitry and other electronic equipment in an enclosed housing, and packaged together with written instructional materials. The packaged electronic circuitry and instructional materials herein are collectively referred to as the “PRODUCT.” The PRODUCT is made available from DESIGN ANALYSIS ASSOCIATES, INC.
If the product fails to satisfy the above warranty, USER must notify DESIGN ANALYSIS in writing within the applicable period specified above and reasonably cooperate with the directions they received from DESIGN ANALYSIS. (c) What DESIGN ANALYSIS Will Do DESIGN ANALYSIS will repair the PRODUCT or will endeavor to provide a replacement of same within a reasonable period of time.
Table of Contents ® User Agreement/WATERLOG Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W-1 Chapter 1 Introduction 1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Check The Model Number . . . . . . . . . . . . . . . . . . . . .
4.3.6 O - Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.7 U - Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.8 C - Averaged Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.9 M - Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.10 X - Exit . . . .
B.4 Holding Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2 B.4.0 ID String(RO) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2 B.4.1 Modbus Address(R/W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2 B.4.2 Stage Units Select(R/W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3 B.4.
Chapter 1 Introduction 1.0 Introduction The WATERLOG® H-3521 is a digital pressure transducer specifically designed for water level monitoring. The H-3521 directly measures water or other fluid pressure over a broad temperature range. Typical applications include monitoring snow pillows to measure snow pack, measurement of water in accumulating rain gauges, and fluid pressure in weirs and dams. The H-3521 can be used in a gas-purge bubbler installation however, Design Analysis Associates, Inc.
1.1 Unpacking The following is a list of items you should have received: ! ! ! ! WATERLOG® H-3521 pressure transducer Main interface cable RS-232 communications cable(optional) Owner's Manual 1.2 Check The Model Number Before installing your new WATERLOG® H-3521, check the information on the label of the sensor enclosure. Check the model number, the range, and the output type to be sure that you have received the instrument you ordered.
Chapter 2 Installation 2.1 Installing the WATERLOG® H-3521 The WATERLOG® H-3521 is a digital pressure transducer specifically designed for water level monitoring. The H-3521 directly measures water or other fluid pressure over a broad temperature range. Typical applications include monitoring snow pillows to measure snow pack, measurement of water in accumulating rain gauges, and fluid pressure in weirs and dams.
2.3 General Installation Recommendations The H-3521 pressure transducer is not recommended for use in applications where silt and mud are problematic. In addition, if the sensor is used in a shallow water application and happens to dry out with mud coating the sensor diaphragm, the diaphragm compliance will be altered and the factory calibration spoiled. The H-3521 sensor will be permanently damaged if it is frozen.
2.5 Making Connections to the Pressure Port The H-3521 has a 1/8" female NPT pressure port for making connections to your pressure source. Apply Teflon tape or anaerobic thread dope to help prevent leaks. The pressure port has a stainless steel plate to prevent the port fitting from spinning in the housing. Make certain the “keeper” plate is in proper position. Whenever possible, use a backup wrench to avoid damaging the enclosure.
2.6 Connecting Your Data Logger The H-3521 has RS-232, SDI-12 and Modbus “smart” digital interfaces together with a 4-20mA analog output. The H-3521 is a SDI-12 V1.3 compliant sensor excluding the CRC commands. It connects directly to any data recorder with SDI-12 capability. The instrument housing has both a 7 pin main interface connector and a 3 pin RS-232 communication connector.
2.6.1 SDI-12 Interface The user must connect pins 5,6, and 7 to the data recorder or the user can power the H-3521 separate of the data recorder and connect just the SDI-12 data line(pin 7). 2.6.2 RS-232 Output When the user wakes up the H-3521 with this port the H-3521 makes a new measurement and updates the outputs (if enabled) and then prints out the measured stage and temperature value.
2.7 Wiring and Installation Precautions ! ! ! The H-3521 requires that the water be at ground potential. Mother Nature takes care of this for surface and ground water. Make certain the pressure port connection is tight Make certain the sintered bronze vent port is not painted or covered 2.8 Programming Your SDI-12 Data Recorder You must prepare your data recorder to receive and record the H-3521 data. Since data recorders differ widely, refer to your recorder manufacturer's directions.
settings can also be changed using the simple RS232 menu, see Chapter 4. MeanCount is the number of raw pressure measurements averaged together to make one measurement sequence. This setting determines how long the sensor will take to make a measurement. MeanCount can be changed as described in chapters 4 and 5. 2.10.1 Setting the Stage Many applications use the pressure sensor to measure water level in a gauge or reservoir. The sensor translates water pressure to water level.
Example of a H-3521 Fluid Extended "Set Current Stage" command: Response Time Values Description Command "aXSCS2.3!" "a0061" 6sec 1 Set the Stage to 2.3 Subsequent Command Response "aD0" a+12.80 Description The new Offset 2.10.2 4-20mA Output The H-3521 has a 12-bit digital-to-analog converter (DAC), precision voltage reference and a 420mA current transmitter. The SDI-12 and 4-20mA sections are isolated from each other with a high voltage digital opto-coupler.
2.11 Testing Before installing the H-3521 in your field location, you may wish to first test the sensor and data logger in your shop or lab. This allows you to become familiar with H-3521 and the data logger in a controlled environment. The H-3521 can be tested with a pressure standard or water filled standpipe. However, for this test to work correctly, the standpipe must be connected to the chassis ground of the data recorder. The wire establishes a ground connection between the water and the data logger.
Chapter 3 Maintenance 3.1 Maintenance Sustained operation of the H-3521 pressure sensor is almost maintenance-free. As with any precision instrument, the calibration should be checked on a regular basis. The instrument has no filters or user serviceable internal parts. 3.2 Precautions ! Check for leaks, make certain the connections to the pressure port are tight. ! Make certain the atmospheric vent is not covered or blocked. ! Make certain the gauge station enclosure is open to the atmosphere.
Chapter 4 Simple Menu Interface 4.0 Simple Menu Interface The H-3521 has a RS-232 interface which is convenient for setup and testing. This chapter is a description of the Simple Menu interface. Included is a description of the menu and each setup option. 4.1 Connecting to the H-3521 The Simple Menu interface is designed to work with a terminal program such as HyperTerminal, Procom or other similar terminal programs. The following table shows the settings that are needed for communication with the H-3521.
4.2 General Operations The H-3521 settings can be made either via the Simple Menu or with extend SDI-12 commands. This chapter focuses on the Simple Menu interface. The menu displays a list of available options. The right column is status information and cannot be edited. At the bottom of the screen is an “Enter Option >” prompt. Enter the desired menu option here, the ENTER key does not have to be pressed. Some options, when selected act as a toggle and will change when selected.
4.3 Menu Options 4.3.1 P - Sensor Mode Options In this sub-menu you can view the current H-3521 power mode settings or other modes if available and change the modes if desired. Refer to section 4.4 for the Sensor Mode Options sub-menu options. 4.3.2 V - Sensor Output Options In this sub-menu you can view the current H-3521 output options and enables. In this submenu you can change these options and enables. Refer to section 4.5 for the Sensor Output Options menu options. 4.3.
screen will refresh and show the new offset. You must make a new measurement “M” to see the results of the new offset. 4.3.7 U - Slope This option is for displaying the current stage slope and also for editing the stage slope. The following prompt at the bottom of the menu. Enter Option >Enter Slope Value[ ] Enter the new stage slope and press the Enter key to input the value. The screen will refresh and show the new slope. You must make a new measurement “M” to see the results of the new stage slope.
4.4 Sensor Mode Options Menu This setup menu is for viewing and editing the H-3521 power modes and other mode enables. 4.4.1 P - Power Mode This option is for changing the H-3521 power mode. The following prompt at the bottom of the menu. Enter Option >Power Mode Value(0-4) [ ] Enter in the desired power mode. Power Modes: 0 = Sleep between measurements 1 = Sleep with sensor bias On (reserved for factory use) 2 = Sleep with sensor bias and reference On (reserved for factory use) 3 = Wait mode.
not average as many measurements. When in this mode the Meancount/Averaged measurements value are not used. But if there is an application where the user needs the H-3521 to measure that fast this mode does work. Therefore, the user may lose some accuracy using this mode because the H-3521 is calibrated in the normal mode with the atmospheric pressure and temperature measured every measurement. After pressing the F key the screen will refresh with the option changed. 4.4.
4.5 Sensor Output Options Menu This setup menu is for viewing and editing the current settings of the 4-20mA output. 4.5.1 Slope This is the current slope that the H-3521 has calculated based on the max and min stage values. 4.5.2 M - Max Stage This setting is the stage value (high) that corresponds to a 20mA output. The following message is displayed. Enter 4-20mA Max Stage[ ] Enter the desired Stage value which corresponds to a 20.00mA output and press ENTER to submit the value.
Enter the desired Stage which corresponds to a 4.00mA output and press ENTER to submit the value. Refer to Chapter-5 for more details about this setting. 4.5.4 U - Update Outputs This option is used to force the H-3521 to make a new measurement and update any enabled outputs. The following message is displayed. Enter Option >Measuring...
Chapter 5 SDI-12 Command and Response Protocol 5.0 SDI-12 Command and Response Protocol This is a brief description of the Serial Digital Interface (SDI-12) Command and Response Protocol used by the WATERLOG® Series Model H-3521 sensor. Included is a description of the commands and data format supported by the H-3521. Refer to the document "A SERIAL DIGITAL INTERFACE STANDARD FOR MICROPROCESSOR-BASED SENSORS.” Version 1.
5.1 Measure Command The Measure Command causes a new measurement sequence to be executed. Data values generated in response to this command are stored in the sensor's buffer for subsequent collection using "D" commands. The data will be retained in the sensor until another "M", " C", or "V" command is executed. Command Response "aM!" "aM1!" "atttn" "atttn" Description Initiate measurement Initiate measurement Where: a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
Example of a H-3521 "aM1!" command: Command Response Time "aM1!" "a0044" 4 sec Response Subsequent Command "aD0" Values 4 Description Make measurement a+AA.AAAA+BB.B+CCCCCCC.CC+DDDDDDD.DD Where: AA.AAAA BB.B CCCCCCC.CC DDDDDDD.
5.2 Concurrent Measurement Command This is a new command since the release of Version 1.2 SDI-12 Specification. A concurrent measurement is one which occurs while other SDI-12 sensors on the bus are also taking measurements. This command is similar to the “aM!” command, however, the nn field has an extra digit and the sensor does not issue a service request when it has completed the measurement. Communicating with other sensors will NOT abort a concurrent measurement.
5.3 Send Data Command The Send Data command returns sensor data generated as the result of previous "aM!", "aC!", or "aV!" commands. Values returned will be sent in 33 characters or less. The sensor's data buffer will not be altered by this command. Command "aD0!" through "aD9!" Response "apd.d ... pd.d" Where: a is the sensor address ("0-9", "A-Z", "a-z", "*", "?"). D0..D9 are upper-case ASCII characters. p Is a polarity sign (+ or -) d.
5.4 Continuous Measurements This is a new command for the Version 1.2 SDI-12 Specification. Sensors that are able to continuously monitor the phenomena to be measured, such as a cable position, do not require a start measurement command. They can be read directly with the R commands (R0!...R9!). The R commands work exactly like the D (D0!...D9!) commands. The only difference is that the R commands do not need to be preceded with an M command.
5.6 Initiate Verify Command The Verify Command causes a verify sequence to be performed. The result of this command is similar to the "aM!" command except that the values generated are fixed test data and the results of diagnostic checksum tests. The data generated in response to this command is placed in the sensor's buffer for subsequent collection using "D" commands. The data will be retained in the sensor until another "M", "C", or "V" command is executed.
5.7 Send Identification Command The Send Identification Command responds with sensor vendor, model, and version data. Any measurement data in the sensor's buffer is not disturbed. Command "aI!" Where: a Response "allccccccccmmmmmmvvvxx...xx" is the sensor address ("0-9", "A-Z", "a-z", "*", "?"). I is an upper-case ASCII character. ll is the SDI-12 version compatibility level, e.g. version 1.2 is represented as "12".
5.8 Change Sensor Address Command The Change Sensor Address Command allows the sensor address to be changed. The address is stored in non-volatile EEPROM within the sensor. The H-3521 will not respond if the command was invalid, the address was out of range, or the EEPROM programming operation failed. Command "aAn!" Response "n" Description Change sensor address Where: a is the current (old) sensor address ("0-9", "A-Z", "a-z", "*", "?").
5.9 Extended Set Current Stage Command The H-3521 processes the pressure sensor input and computes Pressure in PSI units. Stage is computed with a Stage = m * Pressure + b equation. During installation it is convenient to quickly set the H-3521's Stage reading to match the current stage, elevation or pressure of the water as determined by a staff gauge or other datum.
5.10 Extended Read/Write Offset and Read/Write Slope The H-3521 processes the pressure sensor input and computes Pressure in PSI units. Stage is computed with a Stage = m * Pressure + b equation. The Slope (m) and Offset (b) terms are programmable, allowing the user to scale the reading into other engineering units. These commands allow the user to read or write (change) the Slope and Offset terms. The slope is set to 2.3067 and the offset to 0.00 at the factory. With the factory default (2.
5.11 Extended Read/Write Stage Digits This is for reading or writing the stage digits to the right of the decimal point. The stage digits by default is set to 2. Command Response Description “aXRSD!” “a0011” Read Stage Digits “aXWSDd!” “a0021” Write Stage Digits Where: a XRSD XWSD d is the sensor address ("0-9", "A-Z", "a-z", "*", "?"). are upper case characters. are upper case characters.
5.12 Extended Read/Write 4-20mA_Hi and Read/Write 4-20mA_Lo The H-3521 scales the current Stage data to drive the 4-20mA output. The 4-20mA_Hi and 420mA_Lo settings control how the Stage data is processed. The 4-20mA_Lo should be set to the desired Stage corresponding to a 4.00mA output. The 4-20mA_Hi should be set to the desired Stage corresponding to a 20.00mA output. These settings are stored in non-volatile EEPROM within the sensor.
5.13 Extended Read Power_Mode and Write Power_Mode The quadrature, 0-5V, and 4-20mA outputs are updated whenever a measurement is made. For industrial applications such as 4-20mA where the H-3521 is connected to a SCADA or PLC system and low-power is not of concern, the H-3521 can be programmed to make continuous measurements. This command is used to change the power mode. The H-3521 comes from the factory with the power mode set to the Sleep mode.
5.14 Extended Read Measure Rate and Write Measure Rate When the H-3521 is put in power mode 3 it makes continuous measurements based on a measure rate. This command is for reading/writing that measure rate value. The measure rate range is 0255 minutes. When the user sets the measure rate to 0 then the H-3521 makes continuous measurements as fast as the H-3521 will measure, which is about 6 seconds by default. The factory default is 1 minute measure rate.
5.15 Extended Read Mean_Count and Write Mean_Count The H-3521 makes multiple raw sensor measurements, discards the high and low values, integrates (averages) the measurement data and computes Pressure (PSI). The number of raw sensor measurements made for each SDI-12 measurement sequence is programmable. When measuring turbulent water, tides or other special applications Mean_Count can be changed to increase or decrease the number of pressure measurements made during the SDI-12 measurement sequence.
Example of a H-3521 Extended "Read Mean_Count" command: Command Response Time Values Description "aXRMC!" "a0011" 1 sec 1 Read Mean_Count Response Description Command "aD0!" "a+8" Count = 8 Example of a H-3521 Extended "Write Mean_Count" command: Command Response Time Values Description "aXWMC4!" "a0021" 2 sec 1 Write Mean_Count Response Description Command "aD0!" "a+4" Count = 4 H-3521 SDI-12 Command and Response Protocol 5-17
5.16 Extended Read/Write NOAA Mode Enable The H-3521 can be put into a NOAA Mode. In NOAA mode the data collection platform requests data from the H-3521 every second for 3 minutes and then is idle for 3 minutes. When NOAA Mode is enabled the H-3521 measurement response time is less than 1 second. Meaning that the Data command can be sent within 1 second after the measure command is issued. When the enable value is set to a ‘1' the NOAA Mode is enabled and when it is set to a ‘0' NOAA Mode is disabled.
5.17 Extended “XTEST” This command is used for installation or production testing and requires the use of a H-4191 Sidekick interface and a PC. This command causes the H-3521 to transmit unsolicited real-time data for testing purposes. The test mode is used to help troubleshoot the installation by providing a continuous readout of pressure data. This is not compliant with the SDI-12 specification and is not used with data loggers. To activate the test mode, send the command “aXTEST!” from the PC.
Appendix A Specifications Accuracy (Maximum percent of error in measurement) Pressure: Less than or equal to 0.03% of full scale output (FSO) over temperature range referenced to a straight line stretched from zero PSI to maximum pressure Temperature: Internal temperature ±1° C over temperature range Resolution (Smallest change detectable in output signal) Pressure: 0.001% Temperature: 0.001% Linearity Less than 0.03% deviation from a straight line referenced to end points Pressure Hysteresis Less than 0.
Appendix B Modbus Protocol B.1 Modbus Interface Modbus is an industry standard field bus for interconnecting Programmable Logic Controllers (PLCs), intelligent sensors and other devices. The H-3531 FlashLite™ is a Modbus slave and has a serial RS-485 port for connecting to a Modbus compatible host device. See Chapter 2 for the proper connections. Continuous +12Volt power must be supplied to the H-3531 FlashLite™. B.
B.4 Holding Registers There are 25 holding registers in the H-3531 FlashLite™, some are Read/Write registers and some are Read Only registers. The user configurable settings are found in the Holding Registers. Table 2 below shows the contents on the Holding Registers followed by a description of each register.
B.4.2 Stage Units Select(R/W) This holding register allows the user to change the units of the stage that is reported in the input registers. Below shows what values to write to the register to change to the desired units. Stage Units Select Register: = 00 (stage in feet) = 01 (stage in meters) = 02 (stage in inches) = 03 (stage in mm) = 04 (stage in cm) = 05 (raw psi) = 05 (user defined) * factory default B.4.3 Reserved(R/W) This holding register is reserved space for future use. B.4.
B.4.8 Set Current Stage(WO) This holding register allows the user to set the current stage by writing the current stage value to this register. Reading this register is not applicable. This holding register is a 64bit holding register, therefore the value sent to write to this register must be in a 64-bit floating point number format. As shown in the table there is also a 32-bit floating point number register for this command.
The input registers of the H-3531 FlashLite™ hold the measurement data. When the user sends a read command to read an input register the register read initiates a measurement sequence and returns the updated value. Note: The measurement sequence takes approximately 3 seconds to complete before the requested data is sent. The host must know this so that it does not timeout or send a retry. These registers are 64-bit floating point (double precision) numbers.
