DOC027.53.00745 NH4D sc Ammonium Sensor USER MANUAL June 2008, Edition 2 © HACH LANGE, 2007–2008. All rights reserved.
Table of Contents Section 1 Specifications ........................................................................................................................ 5 1.1 Dimensions ................................................................................................................................... 6 Section 2 General Information............................................................................................................... 7 2.1 Safety information ...............................
Table of Contents Appendix A Modbus Register ..............................................................................................................45 Index .......................................................................................................................................................
Section 1 Specifications These are subject to change without notice. General Information Measuring method Ion-selective electrodes for ammonium and potassium, pHD reference electrode and temperature sensor Measuring range 0.2 to 1000 mg/l [NH4–N] Minimum detection limit 0.
Specifications 1.
Section 2 General Information 2.1 Safety information Please read this entire manual before unpacking, setting up, or operating this equipment. Pay attention to all danger and caution statements. Failure to do so could result in serious injury to the operator or damage to the equipment. To ensure that the protection provided by this equipment is not impaired, do not use or install this equipment in any manner other than that specified in this manual. 2.1.
General Information 2.2 General sensor information The sensor was developed for use in municipal waste water applications. The NH4D sc sensor (see Figure 2) with ion-selective electrode (ISE sensor) is a continuous online process sensor for the measurement of ammonium directly in the tank. It operates without reagents and requires no further processing of the sample. The ammonium ions are measured using an ion-selective electrode. The only wear part is the sensor cartridge (see Figure 3 on page 8).
General Information 2.3 Theory of operation The NH4D sc sensor utilizes ion-selective electrode technology to measure ammonium ions (NH4+) in a waste water sample. Well-known interferences of temperature and potassium are compensated by using appropriate built-in sensors. The reference electrode is a differential pH technology and does not have direct contact with the process and therefore, it is particularly stable against drift.
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Section 3 Installation Important Note: Only qualified personnel should conduct the tasks described in this section of the manual. 3.1 Unpacking the sensor Remove the sensor from the shipping container and inspect the sensor for damage. Verify that all items listed in Figure 4 are included. If any items are missing or damaged, contact the manufacturer or distributor.
Installation 4. Connect the sensor cartridge to the sensor (see 3.3 Sensor assembly on page 13). Important Note: The sensor cartridge only fits correctly in the sensor adapter in one position. Pay attention to the markings on the sensor cartridge and on the sensor adapter (see Figure 8 on page 14).
Installation Figure 6 Storage container for sensor cartridge1 1 Storage container 3 Sensor cartridge 2 Black gasket (remove before installation) 4 Cap 1 Save items 1, 2 and 4 for sensor storage. 3.3 Sensor assembly Important Note: Avoid touching the membranes on the sensor cartridge or damage to the sensor may occur. 1. Remove the black gasket. 2. Ensure that the opaque gasket is in place in the sensor adapter. The opaque gasket will be between the sensor and the sensor cartridge.
Installation Note: Do not leave sensor cartridge out of water for more than 30 minutes.
Installation Figure 9 Cap of the storage container as a tool/screwing aid for the locking ring 1 Cap 2 Locking ring 3.4 Installation of the cleaning unit (optional) To install the cleaning unit on the sensor, refer to the installation instructions for the cleaning unit (section 7.4 on page 37). The cleaning interval can be set using the relay control of the sc controller. Select RTC (Real Time Clock) as the signal source. 3.
Installation Figure 10 Example of sensor installation with Rail Mount Kit 16
Installation 3.6 Connect the sensor to the sc controller (non-hazardous location) with quick-connect fittings The sensor cable is supplied with a keyed quick-connect fitting for easy attachment to the controller (see Figure 11 on page 17). Retain the connector cap to seal the connector opening in case the sensor must be removed. Optional extension cables may be purchased to extend the sensor cable length. 1. Unscrew the protective cap from the socket on the controller. 2.
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Section 4 Operation 4.1 Using an sc controller Before using the sensor in combination with an sc controller, refer to the controller user manual for navigation information. 4.2 Sensor setup When a sensor is installed for the first time, the serial number of the sensor is displayed as the sensor name. The sensor name can be changed as follows: 1. Select MAIN MENU. 2. From the Main Menu, select SENSOR SETUP and confirm. 3. Select the appropriate sensor if more than one sensor is attached and confirm. 4.
Operation 4.5 Sensor setup menu (continued) SET NH4–N CONC Entry and display of the NH4–N reference value (lab value) -orCAL.CONFIG.>MATX1 K+ 1 point matrix correction with potassium (see section 4.6.3.2 on page 24) DATE Displays the date of the current correction CONC MEAS 1 SET K+ CONC Saving the currently measured measurement Entry and display of the K+ reference value (lab value) SET NH4–N CONC Entry and display of the NH4–N reference value (lab value) -orCAL.CONFIG.
Operation 4.5 Sensor setup menu (continued) CAL.CONFIG.> FACTORY CAL Selection of the preset sensor code DATE Date of last calibration SENSOR CODE Enter the sensor code CONFIGURE EDIT NAME Entry or editing of the name. Up to 10 alphanumeric characters. MEAS UNITS Selection of mg/L or ppm as measurement unit SET PARAMETER Selection of NH4–N or NH4 TEMP UNITS Selection of °C or °F as temperature unit. TEMP CORR Entry of the temperature correction (–1.5 to +1.5 °C or –2.7 to +2.
Operation 4.6 Calibration The membranes on the ion-selective electrodes are not 100% selective due to other substances that may affect the measurement. Perform a matrix correction to compensate the influences of other ions on the ammonium ISE electrode. Potassium has the largest interference effect on the ammonium membrane. This problem is compensated in the NH4D sc sensor using the integrated potassium electrode.
Operation 4.6.2 Matrix correction overview With the NH4D sc sensor, there are various options (Table 1) for correcting the measured value with laboratory reference values. For the laboratory reference value, a sample is taken for laboratory analysis and the measurement value at that time is stored. Depending on the parameter set, the laboratory reference value of the water sample is stored as ammonium nitrogen (NH4–N) or as ammonium (NH4).
Operation 4.6.3 Matrix correction 4.6.3.1 MATX1 correction (one point matrix correction) Proceed as follows to perform the MATX1: CALIBRATE 1. Select SENSOR SETUP>NH4D SC>CALIBRATE> CAL CONFIG. CAL. CONFIG. 2. Select MATX1 in the selection window and press ENTER. DATE 3. Select CONC MEAS 1. CONC MEAS 1 SET NH4–N CONC READING STABLE? NH4–N: DRIFT K+ DRIFT The currently measured ammonium and potassium values are displayed. The drift indicates whether the measured value is stable. 4.
Operation 6. Analyze the sample immediately after taking the sample as its ammonium content can change quickly. After determining the laboratory reference values for potassium and ammonium, proceed as follows: 7. Select SENSOR SETUP>NH4D SC>CALIBRATE> SET NH4–N CONC. 8. Enter the laboratory reference value for NH4–N and press ENTER to confirm. 9. Select SENSOR SETUP>NH4D SC>CALIBRATE> SET K+ CONC. 10. Enter the laboratory reference value for potassium and press ENTER to confirm.
Operation 10. By confirming the second laboratory value, the Matrix2 correction is activated. 4.6.3.4 MATX2 K+ correction Select MATX2 K+ to calibrate the ammonium and potassium sensor simultaneously at two different measuring points. The calibration is carried out via a standard addition in the sample matrix. Proceed as follows to perform the MATX2 K+: 1. Fill a 10-liter bucket with 3 to 5 liters of sample from the sample flow in which the sensor is immersed. 2.
Operation 8. During the reaction phase of both cuvette/vial tests, add 40 ml from the LCW892 mix standard to the sample in the bucket. 9. With the probe, mix the sample in the bucket once and wait 3 minutes. 10. Select CONC MEAS 2 and wait until the NH4–N and K values are stable (drift should be <0,03 mg/l). 11. Press ENTER. 12. Dilute the sample for the ammonium cuvette/vial test 1:5 and for the potassium test 1:10. 13.
Operation 4.6.3.5 Value correction Value correction offers the option of subsequently correcting a matrix at two different concentrations. Take several samples on various days with different concentrations and perform an analysis of the samples in the laboratory. Note: The concentrations should be in a concentration range of at least half a decade. 1. Note the two displayed ammonium and potassium values, which are measured with the sensor at the time of the sampling. 2.
Section 5 Maintenance Important Note: Only qualified personnel should conduct the tasks described in this section of the manual. 5.1 Maintenance schedule 30 days1 Maintenance task Clean sensor2 x Replace the sensor cartridge3, 4 x Check sensor for damage x Check measured value by lab reference analysis and correct values by matrix correction if required3 x 1 Recommendation: 2 The 3 In 12 months weekly during the first month in operation frequency of cleaning depends on the application.
Maintenance 5. Insert the new sensor cartridge in the sensor adapter. Pay attention to the triangular marking on the cartridge and on the sensor. Important Note: The sensor cartridge only fits correctly in the sensor adapter in one position. Pay attention to the markings on the sensor cartridge and on the sensor adapter. 6. Attach the locking ring over the sensor head and hand-tighten. Note: Use the cap of the storage container as a tool/screwing aid for the locking ring. 7.
Maintenance 5.4 Sensor and Sensor Cartridge Storage Remove the sensor from the sample flow and clean the sensor thoroughly. Short term storage Keep the membranes and the salt bridge moist (NO DISTILLED WATER OR DI WATER). This will help avoid long response times when placing the sensor back in the sample flow. Otherwise, the correct operation of the sensor is no longer guaranteed. Long term storage Important Note: Use the delivered storage container for long term storage.
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Section 6 Troubleshooting 6.1 Error codes When the sensor is experiencing an error condition, the sensor reading on the measurement screen will flash and the relays and analog outputs associated with this sensor will be held. Errors are defined in Table 2.
Troubleshooting 6.3 Troubleshooting 6.3.1 Troubleshooting during operation Symptom Possible cause Corrective actions Calibration too old; calibration was not suitable for the particular case; big change in the waste water matrix Carry out suitable calibration Strongly fluctuating pH values above pH 8, see section 2.3 on page 9. Carry out external pH compensation. Contact our service department.
Troubleshooting 6.3.1 Troubleshooting during operation (continued) Symptom Possible cause Corrective actions Dampness inside the measuring probe/faulty sensor electronics Check the sensor electronics by using the test cartridge (section 7.2 on page 37). 1 Select SENSOR-SETUP>DIAG/TEST>SERVICE> TEST CARTRIDGE>Test cartridge Ready? Press ENTER 2 Compare the displayed values with the guide values. The displayed values should be in the same range as the guide values below.
Troubleshooting 6.3.2 Troubleshooting during calibration Symptom Possible cause Corrective actions SENSOR CODE Sensor code entered incorrectly Using the certificate, check whether the sensor code was entered correctly. If not having the certificate, carry out "Factory Calibration" (Factory cal). CALIBRATING Data transfer from software 1.
Section 7 Spare Parts and Accessories 7.1 Spare parts Description Catalog Number NH4D sc (sensor with 10 m (32.8 ft.) integral cable and one pre-calibrated Sensor Cartridge) Calibrated Sensor Cartridge1 LXV437.99.00001 6188400 Cleaning brush LZY589 Locking ring kit 6176900 Opaque gasket HZD176 1 Sensor cartridges are wearing parts that are not covered by the instrument warranty. 7.2 Accessories Description Catalog Number Cleaning Unit LZY331.99.
Spare Parts and Accessories 38
Section 8 Contact information HACH Company World Headquarters P.O. Box 389 Loveland, Colorado 80539-0389 U.S.A. Tel (800) 227-HACH (800) -227-4224 (U.S.A. only) Fax (970) 669-2932 orders@hach.com www.hach.com Repair Service in the United States: HACH Company Ames Service 100 Dayton Avenue Ames, Iowa 50010 Tel (800) 227-4224 (U.S.A. only) Fax (515) 232-3835 Repair Service in Canada: Hach Sales & Service Canada Ltd.
Contact information 40
Section 9 Warranty and Liability The manufacturer warrants that the product supplied is free of material and manufacturing defects and undertakes the obligation to repair or replace any defective parts at zero cost. The warranty period for instruments is 24 months. If a service contract is concluded within the first 6 months of purchase, the warranty period is extended to 60 months.
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Section 10 Certification Electromagnetic compatibility The device has been tested with an sc100 and sc1000 controller for electromagnetic compatibility (EMC) in the industrial environment in accordance with the following standard(s): EN 61326 (EMC Requirements for Electrical Equipment for Measurement, Control and Laboratory Use) per 2004/108/EC: Supporting test records and compliance certification by the manufacturer. Immunity IEC 1000-4-2 (EN 61000-4-2) Electromagnetic compatibility (EMC).
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Appendix A Modbus Register Table 4 Sensor Modbus Register Tag Name Register # Data Type Length R/W AMMONIUM NH4-N 40001 Float 2 R Discrete Range Min/Max Range Description 0/2000 Ammonium in mg/l AMMONIUM NH4 40003 Float 2 R 0/2576 Ammonium in mg/l K+ 40005 Float 2 R 0/2000 k+ mg/l TEMP DEG C 40007 Float 2 R –30/100 Temp in Deg Celsius TEMP DEG F 40009 Float 2 R –54/180 Temp Fahrenheit POTASS COMPENS 40013 Unsigned Integer 1 R/W 0/1 DATA LOG INTRVL 40014 Uns
Modbus Register Table 4 Sensor Modbus Register (continued) Discrete Range Min/Max Range Tag Name Register # Data Type Length R/W NH4 CONC 1 40079 Float 2 R 0/2576 NH4 mV CONC 1 40081 Float 2 R –250/400 NH4 mV drift CONC 1 40083 Float 2 R –500/500 K+ CONC 1 40085 Float 2 R 0/2000 K+ mV CONC 1 40087 Float 2 R –300/400 K+ mV drift CONC 1 40089 Float 2 R –500/500 TEMP CONC 1 40091 Float 2 R 0/45 DATE 2 40093 Time2 2 R NH4 N CONC 2 40095 Float 2 R 0/2000
Index A R Accessories ............................................................. 37 Replacement of the sensor cartridge ....................... 29 Replacement parts ................................................... 37 C Calibration .......................................................... 19, 22 Cleaning Sensor ............................................................... 29 Components System .............................................................. 17 D Data log ..........................
