3902 Magnolia Rd. Pearland, Texas 77584 Phone: 281-488-0788 Fax: 281-488-7080 E-mail: magtech@isemagtech.com Website: www.isemagtech.com LTM – Series Models: LTM-250 and LTM-350 Magnetostrictive Level Transmitters Instructions & Operation Manual LTM-350_IOM Rev.
Table of Contents Section 1: Warranty .......................................................................................................................................1 1.0 Warranty.......................................................................................................................................................... 1 Section 2: Transmitter Overview ...................................................................................................................2 2.
Table of Contents Section 8: Transmitter Calibration and Troubleshooting................................................................................28 8.0 Calibration ..................................................................................................................................................... 28 8.1 Troubleshooting ............................................................................................................................................ 28 8.
Section 1 Warranty 1.0 Warranty All Magtech products are warranted against defects in materials and workmanship for a period of no less than one year from the date of shipment. The level gage chamber and process connections are guaranteed for the life of the tank or vessel to which it is attached. Floats are guaranteed for two years. Magtech will repair or replace at its discretion those products that fail to perform as specified, with the following exceptions: 1.
Section 2 Transmitter Overview 2.0 General Description The LTM-Series are 2-wire electronic field instruments, suitable for installation in hazardous and non-hazardous locations. Testing and certification has been obtained from different agencies for installation in such areas. This instrument is designed to measure and transmit an analog and/or digital signal proportional to liquid level in a tank. The complete assembly includes an explosion-proof enclosure and attached sensor tube and a magnetic float.
2.3 Gage Mounted Transmitter 2.4 Standalone Transmitter The LTM-Series may be strapped to the outside of the Magtech LG series magnetic level gage. In such an installation, it is used as an accessory transmitter for the visual level gage. The same float used to activate the magnetic gage is also used to activate the magnetostrictive sensor of the LTM and transmit a directly proportional 4/20mA signal.
A stilling well may be used along with the transmitter inside the tank. Stilling-well is a pipe external to the sensor probe and float encasing the entire assembly protecting it from surface agitation or from physical damage due to the length of the sensor probe. A depiction of a transmitter with a stilling well is provided below. Optional Features that are available with the LTM-350 but NOT the LTM-250 are: 1. HART Protocol, which enables: a.
Section 3 Transmitter Description 3.0 Detailed Description The LTM-Series is an assembly of two major components: The Sensor Tube Assembly: This is a 5/8” diameter stainless steel probe, sealed on one end, with the magnetostrictive waveguide in its center. In addition to the magnetostrictive waveguide, the tube also houses the optional temperature sensor and the sensing elements. The tube is made to lengths of 2-30ft. in rigid construction.
A high-speed microcontroller is utilized in the design to process and calculate the elapsed time measurement. Accurate crystals are used for the time based to resolve sub-microsecond timing increments. The binary number, equivalent to the microseconds of the echo travel time is used to calculate the distance of the float and a corresponding digital signal is output. A basic block diagram describing the operation is shown below. Figure 7.
Section 4 Installation 4.0 Gage Mount Installation The LTM-Series can be mounted to the side of a Magtech LG series level gage using special mounting brackets and stainless steel hose clamps. When mounting the transmitter to an LG series gage the active sensor region of the probe should fall within the centerline of the process connections on the gage.
2. Identify Proper Orientation of Transmitter: There are a few possible orientations of the LTM Series transmitters, they are: Do not over tighten the clamps because they will bend and distort. Figure 10. Top view of mounting clamps and sensor probe Figure 9. Possible transmitter configurations Transmitter A is a standard top mount configuration. Transmitter B is a top mount with elbow, usually utilized when there are temperature or head room issues.
4. Remote Mount Electronics Option. Due to process temperature, vibration or accessibility the housing/electronics of the LTM transmitter can be remote mounted as far as 25 ft. The housing/electronics are supplied with a pipemount bracket that can be mounted most nearby posts or pipes with hose clamps. The drawing below depicts a gage mounted transmitter in the top mount remote electronics configuration. There are a variety of ways to install a standalone transmitters (i.e.
4.3 Insulation (against extreme heat/cold) Magtech strongly recommends that an experienced Magtech Technician do insulation of the magnetic level gages at the factory with externally mounted transmitters. If Cryogenic “Hard Skin” cold service type insulation is required, it must be done at the factory due to the custom “TUBE in TUBE” design necessary for removal of the transmitter if needed. (When insulating gages): Magtech level transmitters have a maximum operating temperature of 300 F.
Section 5 Field Wiring 5.0 Recommended Loop Wiring The following is the recommended loop wiring. Figure 13.
The following is the Hart Topology. Figure 14. HART Loop Topology Please visit www.hartcomm2.org to learn more about HART Protocol.
5.1 Area Classification Installation Safety If the instrument is used as an explosion proof (exp) device then exp conduit must be sealed within 18 inches of the termination point – at the instrument. Power must be supplied by an isolated supply. Caution-To reduce the risk of ignition of hazardous atmospheres, disconnect the device from the supply circuit, or area must be known to be non-hazardous, before opening.
Section Transmitter Specifications 6 6.1 Hazardous Locations / General Ratings CSA and CSAUS: Explosion Proof: Class I Div. 1 or 2, Grps. B, C, D Class II, Grps. E, F, G Class III Tamb -40°C to 85°C (-40°F to 185°F) ATEX: Ex d: Sira 10ATEX1308X Ex d IIC T5 Gb Ex tb IIIC T100°C IP66 Db Tamb -40°C to 85°C (-40°F to 185°F) 0344 6.2 Electronic Specifications Supply Voltage: 13 – 36 Vdc (13V @ 20mA) Repeatability: .005% of full scale or .010”, whichever is greater Non-Linearity: .01% of full scale or .
Section 7 Menu Structure and Features 7.0 Pushbutton Operation The menu structure and pushbutton operation of the LTM series transmitters is simple and user-friendly. The electronics module has 3 pushbuttons (from left to right): ↑ : This button is used to increment values and change “Yes” to “No” and “No” to “Yes”. ↓ : This button is used to decrement values and change “Yes” to “No” and “No” to “Yes”. ← : This is the enter button used to execute functions and enter/exit into or out of submenus.
7.1 Menu Structure Main Screen (scrolling): The menu structure has been designed so the end user can make parameter changes relatively fast and easy. Below is a detailed description of these menus. The LTM-250/350 LCD is a 2x8 character screen. The main screen scrolls between the following parameters: 1. 2. 3. 4. 5.
The following is the LTM-250/350 LCD Menu Flowchart Magtech LTM-250 or Magtech LTM-350 SW Rev 1.00.00 HW Rev 1.00.00 Display? Scroll > Level > Intrface* > Temp** > mA Out > % Range SelLngth 30.00 in Lvl Unit in > ft > mm > cm > m Temp Unit** C > F >R > K Sel PV* Level > Interface Sel Alrm FailHigh > FailLow > HoldOut ChgRnge? >>> Yes > No (yes) Sel LRV >>> Sel URV 0.00 in 24.00 in SelDamp 1 sec ROC Fltr 10.0in/s TrmSnsr? >>> Yes > No (yes) TrimZero >>> TrimZero >>> -Busy- TrimSpan >>> 24.
7.1 Menu Structure Continued… Description Manufacturer and Model: Software Revision Status: This is the current software revision. Hardware Revision Status: This is the current hardware revision. Scrolling Option: Allows the user to stop the main menu from scrolling and choose 1 of 5 possible parameters: Engineering Units (level, interface, and temp), Current (mA), or Percentage. Select the desired parameter and then press enter. “Scroll” is the default parameter this option keep the main menu scrolling.
7.1 Menu Structure Continued… Description Select PV: This menu allows the user to select the measurement that controls the transmitter’s current output (mA). LCD Menu (examples) S e l P V L e v e l This menu only appears if the interface (2 floats) option is provided. Select Alarm: The following alarm settings can be chosen: “FailHigh” = 21.00mA “FailLow” = 3.50mA “HoldOut” = holds last good reading until transmitter recovers.
7.1 Menu Structure Continued… Description LCD Menus (examples) Rate of Change (RoC) Filter: This parameter helps ignore erroneous readings from the transmitter’s surroundings. If the user knows how fast the level can change in the vessel (i.e. inches per second) then this parameter should be set at a rate that the level in the vessel cannot suddenly jump to. See section “7.2 Features” for more details. R o C F l t r 1 0 .0 i n / s Trim Sensor: This menu can be used to recalibrate the transmitter.
7.1 Menu Structure Continued… Description Trim Digital-Analog-Converter (DAC): These are factory set parameters used to provide an accurate 4.000mA and 20.000mA. This parameter should not be changed as Magtech uses NIST traceable equipment to calibrate our transmitters and only accredited laboratories for the annual calibration of our equipment. This menu will allow the user to change the accuracy of the transmitter output.
7.2 Features This section will describe in more detail some of the LCD Menus and new features exclusive to models LTM-250/350. Scrolling Option: When choosing not to scroll the main menu the following options can be chosen by pressing the up and down push buttons (exclusively for models LTM-250/350). 1. Display? Scroll (or) Display? Level (or) Display? Display? Intrface (or) Temp (or) Display? Display? mA Out (or) % Range The “Scroll” option will vary depending on how many outputs are configured.
7.2 Features (Exclusive to the LTM-250/350 models) There is an “advance” menu incorporated into the LTM-250/350 models. To access this menu press and hold the increment (↑) button first then while holding the increment button press and hold the enter button for 3 seconds. A new menu will appear on the LCD screen.
7.2 Features (Exclusive to the LTM-250/350 models) This section describes the “advance” menus in detail. ComPort: This menu is currently only utilized at the factory and will not assist in any troubleshooting. When the menu first appears the “No” option is defaulted, simply press enter to bypass this option. If “Yes” is selected and this menu is accidently entered into then the push buttons will be locked out. Simply cycle the power to the instrument to clear the effect of entering into this option.
7.2 Features (Exclusive to the LTM-250/350 models) Please consult factory before attempting this procedure. Document transmitter’s serial number for better assistance. 1-point Calibration Procedure (1pt Cal): The following menu is the 1 –point Calibration procedure. This procedure was designed to help the user get up and running in an emergency.
7.2 Features (Exclusive to the LTM-250/350 models) Field Reversible Transmitter (FlipPrb): An important and key feature of the LTM-250 and LTM-350 Models is the ability to flip (rotate) the entire transmitter 180 degrees. This procedure is only for gage mount transmitters with an elbow connection on them. If the transmitter does not have an elbow connection please contact factory for assistance.
7.2 Features (Exclusive to the LTM-250/350 models) Change Signal (ChngSgnl): The next and final menu in the special features menu is “ChngSgnl” or change signal option. The feature allows the adjustment of the signal being sent down the sensor probe. It can be utilized when one electronics module is being utilized to save settings for various different length sensor probes. This menu has 3 parameters that can be adjusted.
Section 8 Transmitter Calibration and LTM Troubleshooting 8.0 Calibration There really is no need to re-calibrate this instrument. The LTM-Series arrive calibrated to specified measuring ranges at order placement. If the need arises and a recalibration is deemed necessary please follow these instructions carefully. Level simulation will be required at 0% and 100% positions. 1. Verify the “probe length” is not the same as the” measuring range” desired. If so please change accordingly. See Sections 2.
8.2 Power Supply Troubleshooting 2. Water damage to the electronics module or sensor probe. This is potentially the most severe case the symptoms are unpredictable. If there is any suspicion that the transmitter may have incurred water damage please contact the factory to make arrangements to have the unit sent back for factory inspection. Physical and water damage are not covered under warranty. 3. Magnetic Indentation.
Section LTM-350 has HART Protocol 9 9.0 Hart Protocol: General Information The LTM-350 is a HART registered and certified instrument. The section presents how the HART Communication Protocol has been utilized in the LTM-350. This section does not explain what HART Protocol is, please visit www.hartcomm2.org to learn about HART. The following is a flow chart of our HART menu structure.
9.
9.0 Hart Protocol: Menus and Flowchart (continued…) HART Information>>>>>> > Manufacturer Model Unique ID Serial Number Date Sales Order Purchase Order Tag Long Tag Message Descriptor Revision #s>>>>>>>>>>>>>>>>> > Universal rev Fld dev rev Final asmbly num Note 1. Note 2. Note 3. Note 4. When Interf is PV, Interf is displayed. Only applies when interface float is included. Only applies when temperature sensor is included. Value displays 0 if interface float/temperature sensor is not present.
