Instruction manual 862 MIT Multi element Interface Thermo sensor converter August 2006 Part no.: 4416.231 Rev. 2 Enraf B.V. P.O. Box 812 2600 AV Delft Netherlands Tel. Fax E-mail Website : +31 15 2701 100 : +31 15 2701 111 : [email protected] : http://www.enraf.com Instruction manual 862 MIT Page 1 Copyright 2000 - 2006 Enraf B.V. All rights reserved. Reproduction in any form without the prior consent of Enraf B.V. is not allowed. This manual is for information only. The contents, descriptions and specifications are subject to change without notice. Enraf B.V. accepts no responsibility for any errors that may appear in this manual. The warranty terms and conditions applicable in the country of purchase in respect to Enraf B.V. products are available from your supplier. Please retain them with your proof of purchase. Page 2 Preface Preface This manual is intended for technicians involved with the commissioning and service of the Enraf Series 862 Multi element Interface Thermo sensor converter, connected to Enraf series 854 level gauges, 873 SmartRadar or 877 FDI. For mechanical and electrical installation of the 862 MIT and the 864 MTT (Multi Thermo sensor Thermometer), refer to the installation guides of these instruments. Refer also to the list of related documents in Appendix B. A description preceding the technical procedures gives the technical information necessary to understand its functioning. It is recommended to read this description prior to performing any of the procedures. Safety and prevention of damage Refer to the safety chapter in the instruction manual and installation guide of the related instrument for the safety aspects of the instrument and for personal safety and safety conventions. EC declaration of conformity This instrument is in conformity with the protection requirements of EC Council Directive 89/336/EEC. The CE conformity marking fulfills the provisions of EN 50081-2 Generic Emission Standard EN 50082-2 Generic Immunity Standard 73/23EEC Low Voltage Directive when installed, maintained and applied according to requirements as specified in this manual. Legal aspects The information in this manual is the copyright property of Enraf B.V., Netherlands. Enraf B.V. disclaims any responsibility for personal injury or damage to equipment caused by: • • • Deviation from any of the prescribed procedures; Execution of activities that are not prescribed; Neglect of the general safety precautions for handling tools, use of electricity and microwave radiation. Additional information Please do not hesitate to contact Enraf or its representative if you require additional information. Instruction manual 862 MIT Page 3 Table of contents Table of contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Product information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Operating principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Measuring sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Checks before starting commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Selecting temperature dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Tank and temperature probe data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.4 Additional settings for an 877 FDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1 Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2 Data items and error codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Maintenance and trouble shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Temperature error codes (item EM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Temperature status request (item MQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Temperature pointer (items VP and VV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix A Appendix B 5 5 5 5 12 12 12 13 ASCII table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Related documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Page 4 Introduction 1 Introduction 1.1 Product information The 862 MIT (Multi element Interface Thermo sensor converter) is used for interfacing an 864 Multi Thermo sensor Thermometer (MTT). This unit is basically a solid state electronic element selector, containing all necessary hardware for selecting and measuring an MTT with up to 16 spot temperature elements. The 862 MIT must always be used in combination with an 854 level gauge, an 873 SmartRadar or an 877 Field Display & Interface. These instruments must be equipped with an MPU, HPU or OPU option board to interface the 862 MIT. 1.2 Operating principle The 864 MTT contains of 16 spot elements (thermocouples) equally divided over the measuring range. The lowest element acts as the cold junction and its actual temperature is accurately measured by a Pt100 (reference resistor). The spots which are submerged in the product are used for the average product temperature calculation; the remaining spots are used for the average gas temperature calculation. The optional board, located in the 854 level gauge, 873 SmartRadar or 877 FDI, calculates the average product temperature and the average gas temperature. When the instrument is provided with a display the temperature can be displayed. Remote readout of the measured temperature is possible via the 977 Tank Side Indicator (TSI), the 878 panel indicator (CPI) or via tank inventory systems such as Entis Pro. 1.3 Measuring sequence The measuring cycle of the 862 MIT takes approximately 2 minutes and 26 seconds. In that time the following data is measured. Cycle Measurement Cycle Measurement Cycle 1 Rref 5 RTC0 23 2 Rtest 6 RTC0' 24 ÷ 38 3 RPt100 4 Rgnd 7 ÷ 21 22 Measurement UTC0' UTC15 ÷ UTC1 RTC15 ÷ RTC1 39 Utest UTC0 40 Uref Each resistance measurement is measured with 1 mA current and without current. The measurement without current is an offset measurement. In measurement cycle 1 a conversion factor is determined: Hz/ohm. With this conversion factor all other resistance measurements are calculated. This conversion factor is determined with every measurement (2 min 26 sec). In this way an auto calibration of the 862 MIT is obtained. Instruction manual 862 MIT Page 5 Introduction The Pt100 resistance is measured in measuring cycle 3 and in measuring cycle 4 the resistance of the ground wire is measured. The resistance value from the Pt100 resistance is converted into a temperature value via the standard table. This temperature value is used as reference temperature for the thermocouples. The first time the 862 MIT is switched on (with an MTT connected) measurement cycles 7 ÷ 21 determines the wiring sequence of the thermocouple wiring. That wiring sequence is then programmed in item MW (refer to chapter 2.3), and from that moment on, measurement cycles 7 ÷ 21 checks if all elements are still connected in the same order. In measurement cycle 40 another conversion factor is obtained (Hz/V) which is used for all the voltage measurement values in the same way as with the resistance measurements. Figure 1.1 Measuring principle Page 6 Commissioning 2 Commissioning For information how to program items, refer to the instruction manual of the used level gauge or to the instruction manual of the 847 Portable Enraf Terminal. For the connection of the 862 MIT to the instrument, refer to the installation guide of the 862 MIT and the installation guide of the used level gauge. The items which should be programmed / checked, as described in the next sections, must be addressed to the instrument where the 862 MIT is connected. 2.1 Checks before starting commissioning Warning Do not open any of the instruments covers while power is still connected. • • Check the connections of the 864 MTT (refer to installation guide 862 MIT) Check the connection to the instrument (refer to installation guide 862 MIT). Check that the screen of the cable is grounded inside the cable gland. Check the ground connection of the 862 MIT / 864 MTT (refer to installation guides 862 MIT and 864 MTT) Read the sensitive length from the 864 MTT label (or the engraved value on the extension tube). Read the overall length from the 864 MTT label and verify the nozzle height with respect to the zero point (datum plate) of the tank. • • • 2.2 Selecting temperature dimension When the temperature dimension has to be changed from default, all temperature data items will be presented to the new dimension (the format remains the same). Item Name Description W2= Protection level 2 Enter protection level 2. TD= Temperature dimension EX Exit Instruction manual 862 MIT Selects the temperature dimension (format remains unchanged). This item contains one character, which can be: C : degrees Celsius F : degrees Fahrenheit Default set on: C (°C). Exit protection level Page 7 Commissioning 2.3 Tank and temperature probe data Figure 2.1 MTT definitions Item Name Description W2= Protection level 2 Enter protection level 2. MR= Reference resistance Internal floating point format (default: +.00000000E+00 ). The reference resistance value must be set on: +.22200000E+03. MT= Element type Three characters (default: TPL). The element type must be set on: ‘TPL’. MN= Number of elements Two digits (default: 16). The number of elements must be set on: 16. EX Exit Exit protection level. Wait for approximately 3 minutes and then continue with the items on the next page. Page 8 Commissioning Item Name Description W2= Protection level 2 Enter protection level 2. MTT wiring request This is a data item which holds the detected wiring sequence from the thermocouple wiring (blue wires). The wiring sequence must be copied in item MW. Item RW can only be read if item MW is set to its default value (all 0’s). RW MW= MTT wiring connections Sixteen hexa-decimal characters (default: 0000000000000000). Give the found wiring sequence from item RW into item MW. Note 1: When entering item MW with the Portable Enraf Terminal, the display will be cleared after entering the 15th character. Continue with entering the last character and press return. All 16 entered characters will be repeated at the top line of the PET. Note 2: To disable the first spot temperature element (Pt100) from the average product temperature calculation, set the first character of item MW to ‘F’, and all the others as found in item RW. Only valid from software versions: MPU B1.3, HPU B2.1 and OPU B1.1. EX MK= Sensitive length MTT Format according to item LD (default: +030.0000). Check the value for the sensitive length of the MTT on the identification plate of the 864. Enter that value in item MK. MO= Temperature element offset Format according to item LD (default: +000.0000). Item MO represents the distance from tank zero to the first temperature element (Pt100 spot). MO can be found as follows: height mounting nozzle 864 MTT (with respect to tank zero) - overall length. MI= Format according to item LD (default: +000.1000 m). The distance MI is a hysteresis around the switching point of the temperature elements. Switch hysteresis MP= Product immersion depth Format according to item LD (default: +000.5000 m). The distance MP specifies the minimum required liquid level above a thermocouple before it is taken in the average product temperature calculation. MG= Gas immersion depth Format according to item LD (default: +000.5000 m for 854 / 873 and +000.1000 m for 877). The distance MG specifies the minimum required distance below a thermocouple before it is taken in the average gas temperature calculation. VR= Reference voltage Internal floating point format. Must be set to: +.18500000E+04. VT= Test voltage Internal floating point format. Must be set to: +.13567000E+04. TU= Temperature status conversion One character (default: ‘T’). This item is used to indicate the temperature status character incase of a reduced or not guaranteed temperature accuracy. Exit Instruction manual 862 MIT Exit protection level. Page 9 Commissioning 2.4 Additional settings for an 877 FDI Item Name Description W2= Protection level 2 Enter protection level 2. OB= Option board Three characters. This item informs the XPU what option board is installed. That can be: MPU - for MPU optional board HPU - for HPU and OPU optional board EG= Enable temperature transmission One character; either “D” or “E”. With this item can be selected if the 877 FDI shall answer on a temperature request (C-record), addressed to the connected level gauge. E - transmission of temperature record is enabled D - transmission of temperature record is disabled TF= Temperature source selection One character; either “I” or “E”. This item selects if there is a temperature measurement inside the indicator (Internal) or to be fetched from the Enraf field bus (External). I - Internal (MPU, HPU, or OPU option board installed) E - External Exit Exit protection level. EX Page 10 Operation 3 Operation 3.1 Display For operation of the display and the information on it, refer to the instruction manual of the applicable level gauge or 877 FDI. Below, only an overview is given which display formats gives information about the 862 MIT Multi element Interface Thermo sensor converter / 864 MTT Multi Thermo sensor Thermometer. Display format A C D Displayed information Product level and average product temperature Average gas temperature and status Average product temperature and status 3.2 Data items and error codes Below, a summary is given of the available data items and error codes. There is no operational command. Item AG AP MQ MU U0 - UF V0 - VF VV EM FM FH M0 H0 Description Measured / calculated data Average gas temperature Average product temperature Temperature status request Test resistance (standard floating point format) Calculated spot positions Spot temperatures Temperature pointer value (first set the temperature value pointer item VP, then request for item VV) Error codes Error MPU / HPU / OPU request Fatal MPU errors Fatal HPU / OPU errors Last fatal MPU error Last fatal HPU / OPU error Instruction manual 862 MIT Page 11 Maintenance and trouble shooting 4 Maintenance and trouble shooting 4.1 Temperature error codes (item EM) This item contains the most recent temperature error encountered by the MPU, HPU or OPU board. Error codes 22xx are from the MPU board, 24xx are from the HPU board and 26xx are from the OPU board. 2x00 2x50 2x51 2x52 2x53 2x54 2x55 2x56 2x57 2x58 2x59 2x60 2x61 2x62 2x63 2x64 2x65 2x67 2x68 1 2 ) ) *) No error, value at initialization Element connected to CN2-0 detected absent Element connected to CN2-1 detected absent Element connected to CN2-2 detected absent Element connected to CN2-3 detected absent Element connected to CN3-4 detected absent Element connected to CN3-5 detected absent Element connected to CN3-6 detected absent Element connected to CN3-7 detected absent Element connected to CN4-8 detected absent Element connected to CN4-9 detected absent Element connected to CN4-10 detected absent Element connected to CN4-11 detected absent Element connected to CN5-12 detected absent Element connected to CN5-13 detected absent Element connected to CN5-14 detected absent Element connected to CN5-15 detected absent Wrong sequence number in transmitted data; 862 MIT will be reset. 1) Overflow bit set in transmitted data. Check thermocouple wiring connections Communication error with 862 MIT; check wiring and grounding between 862 MIT and connected instrument Check on too high leak current Refer to section 1.3 Measuring sequence 2x69 2x72 2x73 2x74 2x75 2x76 2x78 2x79 2x80 2x81 2x82 2x83 2x86 2x87 2x88 2x89 2x90 2x92 CRC error 1) Item RW determined, but not copied into MW Syntax error in item MW (compare MW with RW) Unable to detect wiring sequence. One or more elements were detected absent General MIT error (R_ref and / or R_gnd failed) *) U_TC0 and / or U_TC0' failed *) Item MR not set to any value Calibration fail; items VR and / or VT not (correct) set Ratio R_test / R_ref invalid (should be 0.75) *) Ratio U_test / U_ref invalid *) R_TC0 >100 ohm (thermocouple 0 open loop) *) 330 ohm > R_TC0' > 430 ohm. Check if CN1-19 is unconnected and if item MR has the correct value 2) Leak current too large. Check with item VV10,00. This should be lower than 250 nA. Check grounding of all cabling to 862 MIT and level gauge. R_TCi error. Thermo elements possibly not connected in the right order. *) On resistance of one of the FETs is too high. Check if item MR has the correct value Measured thermo voltage of an element is too high Floating point calculation failure (on processor board) No communication with MIT during last 10 seconds. Check cabling between 862 MIT and connected instrument. If one element is detected absent it could very well mean that the thermocouple wiring to the 862 MIT is not correct connected or the FET switch in the 862 MIT is not correct working. 4.2 Temperature status request (item MQ) Four bytes status information (B0 B1 B2 B3) with the following meaning: Status byte 0: Contains the characters ‘0’ ÷ ‘F’, indicating the highest immersed spot element of the MTT. At start up: ’I‘. Status byte 1: Status byte 2: bit 0 : General temperature fail bit 0 : Last valid level used 1 : Fail in average product temperature 1 : Manual level used 2 : Fail in average gas temperature 2 : Level time out 3 : Level exceeds lowest spot element 3 : Device not calibrated 4 : Level exceeds highest spot element 4 : Exceeding differential temp. range 5 : Spot element fail (one or more spots defect) 5 : Out of specified temperature range 6 : 1 6 : 1 7 : 0 7 : 0 Status byte 3: bit 0 : No previous store command 1÷5 : 0 6 : 1 7 : 0 Page 12 For decoding of the status bytes, refer to the ASCII table in appendix A. Maintenance and trouble shooting 4.3 Temperature pointer (items VP and VV) With the temperature value pointer item VP several important calculation results can be selected which then can be requested by the temperature pointer value item VV. First load the pointer (item VP) with 2 digits (v, w), a separator which can be a ‘ . ’ (point) or a ‘ , ’ (comma), and another 2 digits (x, y) according to the table below. vw . xy 00 01 . . 01 - 15 00 - 01 10 10 10 10 10 . . . . . 20 21 22 30 Selected value Dimension UTC1 - UTC15 UTC0 - UTC0' µV µV 00 01 02 07 08 Sigma leak current Uref / Utest Element being measured fR_ref fR_ref-offset µA Hz Hz . . . 01 - 15 01 - 15 00 - 03 Ron1 - Ron15 RTC1 - RTC15 RTC0 , RTC0' , Rgnd , RPt100 Ω Ω Ω . 00 - 15 Element temperature in 8 digits depending on item TD Next, the item VV holds the value of the selected quantity in floating point format. Item Name Description VP= Temperature value pointer Temperature value pointer; format: 2 digits, separator, 2 digits (refer to table above). Example: VP=22.03: value pointer loaded to request the Pt100 element resistance VV Temperature pointer value Temperature pointer value; standard floating point format. This item hold the value requested by item VP (refer to table above). Example: the requested Pt100 element resistance. Instruction manual 862 MIT Page 13 Appendix Appendix A Page 14 ASCII table Appendix Appendix B Related documents Installation guide 862 MIT MIR Installation guide 863 MTT Multi Thermo sensor Thermometer Installation guide 854 Advanced Technology Gauge Instruction manual series 854 ATG level gauge Installation guide 854 XTG Servo gauge Instruction manual series 854 XTG level gauge Installation guide 873 SmartRadar Control Unit & Antenna Unit Instruction manual 873 SmartRadar Installation guide 877 FDI Field Display & Interface Instruction manual 877 FDI Field Display & Interface Item documentation for Enraf series 854 level gauges, 873 SmartRadar, 877 FDI Instruction manual 862 MIT Page 15 Index Index 862 MIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 864 MTT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Average gas temperature . . . . . . . . . . . . . . . . 5, 11 Average product temperature . . . . . . . . . . . . . 5, 11 CE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Display format . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Electrical installation . . . . . . . . . . . . . . . . . . . . . 3, 7 Element type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Enable temperature transmission . . . . . . . . . . . . 10 Error MPU / HPU / OPU request . . . . . . . . . . . . 11 Fatal HPU / OPU errors . . . . . . . . . . . . . . . . . . . 11 Fatal MPU errors . . . . . . . . . . . . . . . . . . . . . . . . 11 Gas immersion depth . . . . . . . . . . . . . . . . . . . . . . 9 Installation electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Items AG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 AP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 EG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 EM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11, 12 FH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 FM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 H0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 M0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 MG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 MO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 MQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11, 12 MR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 MT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 MU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 MW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6, 9 OB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 RW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 TD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 TF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 TU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 U0 - UF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 V0 - VF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 VP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11, 13 VR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 VT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 VV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11, 13 Page 16 Last fatal HPU / OPU error . . . . . . . . . . . . . . . . . 11 Last fatal MPU error . . . . . . . . . . . . . . . . . . . . . . 11 MTT wiring connections . . . . . . . . . . . . . . . . . . . . 9 MTT wiring request . . . . . . . . . . . . . . . . . . . . . . . . 9 Number of elements . . . . . . . . . . . . . . . . . . . . . . . 8 Option board . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 HPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 MPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 OPU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Product immersion depth . . . . . . . . . . . . . . . . . . . 9 Reference resistor . . . . . . . . . . . . . . . . . . . . . . 5, 8 Reference voltage . . . . . . . . . . . . . . . . . . . . . . . . 9 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Sensitive length MTT . . . . . . . . . . . . . . . . . . . . . . 9 Spot elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Switch hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . 9 Temperature dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 element offset . . . . . . . . . . . . . . . . . . . . . . . . . 9 pointer value . . . . . . . . . . . . . . . . . . . . . . . . . 13 source selection . . . . . . . . . . . . . . . . . . . . . . 10 status conversion . . . . . . . . . . . . . . . . . . . . . . 9 status request . . . . . . . . . . . . . . . . . . . . . 11, 12 value pointer . . . . . . . . . . . . . . . . . . . . . . . . . 13 Test resistance . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Test voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Thermocouples . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2