KROHNE BM 70 A Operating Instructions Manual
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KROHNE BM 70 A Operating Instructions Manual

KROHNE BM 70 A Operating Instructions Manual

Level-radar
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DIN A4: 7.02224.32.00
©
KROHNE 01/2001
US size: 7.02224.72.00
GR/LD
This documentation is designed to help the user and/or systems
planning engineer select the optimum instrument type, assess
measurement properties, and plan the mechanical and electrical
installation.
Detailed information on installation, operation and control of type
BM 70 A/P, BM 702 Level-Radar instruments is contained in the
"BM 70 A/P or BM 702 Installation and Operating Instructions" and
the Short Manual "Getting Started with BM 70 A", which are supplied
together with the instruments.
The structure of this documentation is modelled on the lines of DIN V 19259 V Standard.
Project Engineering
Guidelines
BM 70 A, BM 70 P, BM 702
LEVEL-RADAR
Contents:
1
2
3
4
5
6
7
8
9
Page
2
3
5
6
11
14
23
34
36
38
39
40
40

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Summary of Contents for KROHNE BM 70 A

  • Page 1: Table Of Contents

    Power supply “BM 70 A/P or BM 702 Installation and Operating Instructions” and 10 Certificates and approvals the Short Manual “Getting Started with BM 70 A”, which are supplied 11 Order information together with the instruments. 12 External standards, codes and directives 13 Quality assurance The structure of this documentation is modelled on the lines of DIN V 19259 V Standard.

  • Page 2: Application Range

    BM 702 is a 2-wire Radar for the simpler applications in storage tanks, process tanks, stilling wells and side vessels. Hazardous-duty versions BM 70 A/P, BM 702 Ex are suitable for use in Ex-Zone 0, 1 and 2. In Germany (and, depending on the respective radio approval, in some other countries as well), its use is restricted to closed tanks or containers made of metal or concrete.

  • Page 3: Mode Of Operation And System Structure

    The linearity correction is deduced via control oscillator reference measurement of the oscillator. The non-linearity is corrected up to 98% (BM 702/BM 70 A). An immediate frequency regulation is necessary with the BM 70 P device because of the higher demand on the Microwave Phase measuring accuracy.
  • Page 4 2.2 Signal processing (digital) The radar signals are further processed digitally by a microprocessor. The processing system is distin- guished by intelligent procedures taking into consideration plausibilities and history. 2.3 Advantages of radar technology Compared to alternative level gauging methods, radar technology offers numerous advantages: •...

  • Page 5: Input (Measured Quantity)

    Volume measurements are possible by entering a conversion table (max. 50 points). The strength of the reflected signal can be measured for qualitative assessment of the tank product or its surface (only BM 70 A/P). 3.2 Measuring range [0.5...20/35/40/100 m] Minimum tank height: 0.5 m (1.64 ft)

  • Page 6: Output

    4 Output 4.1 Variants BM 70 A, BM 70 P: Variant Comments Described in Section ® ® Ex-e current output HART Ex-e; active; HART protocol; 4.2 + 4.4 together with switching output and digital input ® Ex-i (IS) intrinsically safe; passive; HART protocol 4.3 + 4.4...
  • Page 7 Operating data: max. 100 mA / 30 V DC or 30 V AC. Internal resistance: ≤ 20 Ω ® 4.3 Ex-i (IS) current output HART (type of protection: Ex de [ia]) BM 70 A, BM 70 P: Level, distance, volume FRQYHUVLRQWDEOH or reflection; Function and error identification; passive output (current sink) Current 4-20 mA;...
  • Page 8 HART HART Master 4...20 mA b) As a multipoint connection (multidrop) with up to 15 devices (BM 70, BM 70 A/P, BM 702 or ® other HART equipment), in parallel on a 2-wire bus: A BM70 A/P, BM 702 is normally used with Ex-i current output, but an Ex-e current output can also be used (constant 4 mA in both cases.)
  • Page 9 (conversion table), reflection, parameters and status. A PC can configure any BM 70 A/P via the bus (RS 485/RS232 converter required) by means of the PC-CAT program, provided no Master is active. The maximum cable length - excluding amplifier - is 2000 m (6500 ft).
  • Page 10 • Since signal reflections at the line ends can interfere with communication, both the line beginning (at the computer system) and the line end (at the last device) should be terminated with the typical surge impedance of the cable (120 Ω). Inside the BM 70 A/P, changeover can be made between "high-resistance" und "120 Ω".

  • Page 11: Measuring Accuracy

    Since the measuring process primarily determines distance, measuring accuracy can only be specified as a function of the distance. For that reason, all data given in this Section 5 are based on the mea- sured distance. BM 70 A: Accuracy inch cm ±...
  • Page 12 Repeatability is equal to half the value for the error of measurement. 5.4 Measured value resolution/hysteresis Measured value resolution is: 1 mm / 0.04" for BM 70 A and BM 702, and 0.1mm / 0.004" for BM 70 P Hysteresis is at least 20 times smaller than the error of measurement.
  • Page 13 5.6 Turn-on drift / turn-on characteristics After the BM 70 A has been switched on, a rough measured value is displayed after about 1 minute. The first self-calibration is completed after about 2 minutes. Full measuring accuracy is attained after 30 minutes operating time.

  • Page 14: Application Conditions

    If possible, mount the flange in that way: the axis of the tank wall converter (direction display) flange is oriented tangentially to the tank wall (example): display BM 70 A/P, BM 702 converter Page: 14 BM 70 X Project Engineering Guidelines 01/2001...
  • Page 15 (multiple reflections!) (multiple reflections!) (interference reflections!) If these recommendations cannot be followed due to the tank geometry, please consult KROHNE! B) Still well or Wave-Guide Any position of the still well or the Wave-Guide on the tank is allowed. (For layout: refer also to Section 6.1.4; for block distance: refer to Section 3.3)
  • Page 16 Use of a still well or Wave- Guide is positively recom- mended for horizontal cylindrical tanks (avoidance of multiple reflections): 6.1.3 Mounting on tank fitting Horn antenna Should be mounted on the tank fitting as close to the horizontal as possible (deviation ≤ ± 2°). Exception: when product surface is not horizontal (e.g.
  • Page 17 Exception: When the tank nozzle is symmetrical, the antenna may end in the nozzle in order to enlarge the measuring range (minimum dead zone to tank cover, see Sect. 3.3 "block distance" and Sect. 5.2 "error of measurement"): Tank nozzle Narrow tank nozzle If the inside diameter of the nozzle is smaller than the diameter of the antenna, and the nozzle is accessible from the inside of the tank, the antenna can be mounted from the inside with an extension...
  • Page 18 6.1.4 Mounting on still wells Antenna Outside dia. Ø type 76 mm / 2.99” 80 mm / 3.15“ Pressure 2, 2S* 100 mm / 3.94“ equaliza- 140 mm / 5.51“ tion hole 152 mm / 5.98” 4, 4S* 200 mm / 7.87“ <...
  • Page 19 The so-called "Wave-Guide" is a pipe of 30 mm (1.18“) outside and 25 mm (0.98“) inside diameter, that is bolted direct to the BM 70 A flange system (in the same way as an antenna extension). It functions in the same way as a still well and can be used for clean products. The Wave-Guide is not practical in conjunction with the BM 70 P as it will not provide high measuring accuracy.
  • Page 20 6.2.6 Climate class Locations exposed direct to open-air climate, D1 Severity in conformity with EN 60654-1 6.2.7 Ingress protection Signal converter: IP 66 / IP 67 (equivalent to NEMA 6) 6.2.8 Shock resistance The device withstands the impact test in conformity with EN 61010, Section 8.2 with 0.5 J energy and the drop test to prEN 50178:1994.
  • Page 21 Table of dielectric permittivity The following overview is based on data from the literature, tabular data, application experience and laboratory measurements (ε values are rounded guide values for the examples given below). ε Product group Examples INORGANIC hydrogen cyanide HCN water H2O hydrazine N2H4 sulphuric acid H2SO4...
  • Page 22 6.3.3 Product limitations Radar-based level measuring devices are not suitable for operation with the following products: • liquid ammonia (NH ) under pressure • liquid hydrogen (H • liquid helium (He) 6.3.4 Product temperature (unlimited) The product temperature is not relevant provided the ambient temperature (see 6.2.2) and the flange temperature (see 6.2.3) are within the specified limits.

  • Page 23: Design

    7 Design 7.1 Models BM 702 with horn BM 70 A Wave-Stick BM 70 A Wave-Guide BM 70 A/P with horn antenna 7.2 Dimensions, weights Basic version: High-temperature version: 313 (12.32") 313 (12.32") 214 (8.42") 226 (8.89") 226 (8.89") 176 (6.89")
  • Page 24 Wave-Stick: Wave-Stick with hygienic connections: ',1GDLU\ ZLWKDGDSWHUIRU7UL&ODPS Options: Tri-Clamp 2", 3", 4" 292mm 260mm 11.5" SMS 51 mm, 63 mm, 76 mm 10.2" DIN 11851(dairy) DN 50, DN 65, DN 80 313mm/12.3" 226mm/8.9" 384mm 351mm 15.3" 13.8" 272mm 10.7" 1mm/0.4" PTFE plate Ø...
  • Page 25 7.3 Choice of antenna type and size This is a BM 70 A recommendation for the optimum application range, based on application experience, in order to minimize potential problems. If the recommended antenna cannot be accepted, any other configuration may also be tested.
  • Page 26 Aluminium with electrostatic powder coating to DIN 55990-3 Sight window: Glass 7.4.2 Flange system (Antenna, extensions and flange or flange plating) Available materials for BM 70 A/P, BM 702 flange systems (in contact with the product): DIN No. AISI equivalent Versions with horn antenna or Wave-Guide: Stainless steel 1.4571...
  • Page 27 The following list is based on manufacturers’ information and provides a rough overview of the chemical resistance of available seals and gaskets that come into contact with the tank product. However, KROHNE cannot assume any guarantee for the correctness of the information. Respon- sibility as to suitability rests solely with the user.
  • Page 28 7.5 Process connection The process connection is made by way of standard flanges of size DN 50-200 or relevant ANSI sizes (dependent on the version). For the Wave-Stick various hygiene connections are additionally available: Antenna 335mm 223mm 148mm 110mm 384mm length: (13.2“) (8.8“)
  • Page 29 0.5 - 2.5 mm² (solid conductor: max. 4 mm²) PE conductor or FE funct. GND (see 9.3): U-clamp terminal (max. 4 mm² conductor cross section) Cable entries: BM 70 A/P: 3x M25×1.5 ZLWKVWDQGDUGFDEOHJODQGFDEOHFODPSLQJDUHD PP BM 702: ® 3x M20×1.5 (alternatively: Quickon...
  • Page 30 ® ® Current output HART , Ex e: Ex-i current output HART Switching output Current max. 100mA/30V DCAC output Digital Current 32 31 input output U min.= 8V 82 81 42 41 32 31 4-20mA 5...28V= 4-20mA Ex-i (IS) U max.= 30V max.500 Ω...
  • Page 31 (information on other pressures provided on request). When a liquid is used for purging, this may interfere with the functioning of the BM 70 A/P, BM 702 during this process. Continuous purging with gas is not a problem, as it does not interfere with measurements.
  • Page 32 • Trend and evaluation of the signal during operation PC-CAT works on all IBM-compatible PC’s using Windows 9x or NT. PC-CAT Version 4.00 and higher can communicate with all current KROHNE level radar gauges ® including BM 70 A/P, and BM 702 versions, also with HART protocol and RS 485.
  • Page 33 PC-CAT display (example): BM 70 X Project Engineering Guidelines 01/2001 Page: 33...

  • Page 34: User Interface

    • BM 70 A/P: 4 keys next to the local display (the housing of the electronics compartment must be opened; also allowed in the hazardous area) •...
  • Page 35 8.3 Parameter setting At the least the following basic parameters must be known in order to be able to configure the BM 70 A/P, BM 702 measuring system: • Tank height (from tank fitting to tank bottom) • Maximum level likely to occur •...

  • Page 36: Power Supply

    (typically) harmonic component 24V DCAC 24 V DC -25% 18-31.2 V 7.5-10 W within limits of +30% tolerance (BM 70 A/P) 24 V AC -25% 18-26.4 V 45-66 Hz 10 W +10% 115/230V 115 V AC -25% 85-127 V...
  • Page 37 Type BM 70 A/P, BM 702 level gauges do not feature any device for switching or disconnection. Class of protection The BM 70 A/P level gauge is designed for safety class 1 in conformity with VDE 0106 Part 1. DC/AC power supply 24 V DCAC When connected to a “functional extra-low voltage with safety separation“...

  • Page 38: Certificates And Approvals

    Authority Certificate No. Class Device type Europa PTB PTB99 ATEX2061X II1/2G EEx de IIC T6..T1 (Z.0) BM 70 A/P;BM 700 II1/2G EEx de [ia] IIC T6..T1 (Z.0) BM 70 Ai/Pi II1/2G EEx ia IIC T6..T1 (Z.0) BM 702i J.I. 3000813 I Div.1 Gr.B/C/D;...

  • Page 39: Order Information

    11 Order information A) Summary of all technical information relevant to the order: BM 70 A/P, BM 702 Level-Radar ♦ Connecting flange: ......_____________________________________________ ♦ Flange and antenna material:.._____________________________________________     ♦ Waveguide seal:......Viton FFKM Kalrez2035 other ___________ ...

  • Page 40: External Standards, Codes And Directives

    DIN 55990: 1979-12: Verification of paints and similar coating materials; Powder mould coatings ..[in German] ® HUG-3: HART FSK Physical Layer Specification Rev. 7.2: 1993-05 13. Quality assurance KROHNE Messtechnik GmbH & Co. KG is certified in conformity with: • DIN ISO 9001 / EN 29001 • ATEX 100a •...

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