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 1 Purpose
The DTM2 multipoint temperature transmitters (hereinafter referred to as "DTM2" or "transmitters") are designed for continuous monitoring of the temperature of liquid products in process reservoirs and commercial tanks in several points by referring to a filling-in height.
The DTM2 transmitters perform automatic contact measurement of the temperature of a medium under monitoring in particular points through a reservoir height.
The DTM2 transmitters perform automatic contact measurement of the temperature of the medium under monitoring in points with a spacing multiple of 0.25 m by referring to a reservoir height.
The maximum number of measurement points for the DTM2 transmitter is equal to 16.
The transmitters are used in automation systems employed in production facilities of oil-and-gas, petrochemical, chemical, electric-power, metallurgy, food and other industries, which use apparatuses with an atmospheric or excess (not higher than 0.15 MPa) pressure.
The DTM2 transmitters are designed for installation on objects in zones of classes 1 and 2 in compliance with GOST R 51330.9. These zones are characterized by possible formation of mixtures of combustible gases and vapors with air. The mixtures belong to category IIB of temperature classes T3, T4 or T5 depending on the temperature of a mounting flange.
The DTM2 transmitters are made in the explosion-proof version in compliance with the requirements set forth in GOST R 51330.0 and GOST R 51330.10. Their explosion-proof system is of the "Spark-proof electric circuit" type and provides the explosion-proof level for explosion-hazardous mixtures of category IIB according to GOST R 51330.11 of temperature classes T3, T4 or T5. The transmitters have the "1ExibIIBT3/T4/T5 X" explosion-proof marking (depending upon the temperature of the mounting flange) in compliance with GOST R 51330.0. They may be used in explosion-hazardous zones in conformity with the requirements set forth in Chapter 7.3 of the Electrical Equipment Installation Regulations (the sixth edition) or other standard and engineering documents regulating the use of equipment in explosion-hazardous zones.
Sign "X" for the DTM2 transmitters indicates the possibility of their use in set with the BSD-1 transmitter interfacing unit, TU 4217-026-29421521-04 or with other devices of the "Spark-proof electric circuit" type, which provide the explosion-proof level for explosion-hazardous mixtures of category IIB and possess the following parameters of spark-proof outputs: U0 ≤14.3 V and I0 ≤80 mA.
The transmitters are entered in the State Register of Measuring Equipment.
2 Medium to Be Monitored
Oil, oil products, solvents, acids, alkali and other corrosive and non-corrosive media.
The resistance of the transmitters to corrosive media is limited by materials used, which are in contact with the medium under monitoring. These materials include the 12Kh18N10T stainless steel and polytetrafluorethylene.
3 Composition of Devices
3.1 The transmitters consist of:
– a sensitive element (SE) incorporating integral thermometers (IT);
– a primary transducer (PT) comprising a microcontroller (MC) and a nonvolatile memory.
The DTM2 transmitter sensitive element is made as a cable-rope in the fluoroplastic sheath. The integral thermometers are arranged inside the sheath with a spacing multiple of 0.25 m. Secured to the lower portion of the sensitive element is a load to provide SE tensioning. The primary transducer in the aluminium alloy cast casing is installed in the upper portion of the transmitter sensitive element beyond the reservoir.
3.2 Table II.4.1 presents the assortment of the DTM2 transmitters under production.
Table II.4.1
|
Designation |
Transmitter version |
|
DTM2-0 |
"0" ordinary |
|
DTM2-1 |
"1" increased accuracy |
4 Specifications
4.1 Table II.4.2 shows the basic specifications and operating conditions of the transmitters.
Table II.4.2
|
No. |
Parameter |
DTM2 |
|
1. |
Sensitive element length |
from 1.5 to 16 m |
|
2. |
Number of measurement points |
up to 16 |
|
3. |
Temperature of medium under monitoring |
from minus 45 to +125 °C |
|
4. |
Pressure of medium under monitoring |
not higher than 0.15 MPa |
|
5. |
Explosion-proof system marking |
1ExibIIBT3/T4/T5 X, GOST R 51330.0 |
|
6. |
Device casing protection level |
IP68, GOST 14254 |
|
7. |
Climatic version |
OM1.5, GOST 15150 |
|
8. |
Ambient temperature |
from minus 45 to +85 °С |
|
9. |
Atmospheric pressure change limits |
from 84 to 106.7 kPa |
|
10. |
Atmosphere type |
III and IV (maritime and seaside-industrial) |
|
11. |
Service life |
at least 10 years |
|
12. |
Mass |
4.7 kg, max. |
|
13. |
Overall dimensions |
145x215x(130+LSE*), mm, max. |
* LSE – sensitive element length.
4.2 Viscosity is unlimited when the medium under monitoring fails to get solidified on the transmitter sensitive element, and there are no deposits on the transmitter.
4.3 The limits of the admissible absolute error in measuring the temperatures by the DTM2-0 transmitter are as follows:
– within the temperature range of the medium under monitoring from minus 45 to minus 10 °C: ±2 °C;
– within the temperature range of the medium under monitoring above minus 10 to +85 °C: ±0.5 °C.
– within the temperature range of the medium under monitoring above +85 to +125 °C: ±2 °C.
4.4 The limits of the admissible absolute error in measuring the temperatures by the DTM2-1 transmitter are as follows:
– within the temperature range of the medium under monitoring from minus 45 to +85 °C: ±0.5 °C;
– within the temperature range of the medium under monitoring above +85 to +125 °C: ±2 °C.
4.5 Electrical parameters and characteristics of the DTM2 transmitter
4.5.1 The transmitters are supplied from the secondary device with a DC spark-proof voltage of +12 V. Current consumed by the transmitters does not exceed 40 mA.
4.5.2 As to the level of protection against electric shock, the transmitters are referred to protection class III in compliance with the requirements set forth in GOST 12.2.007.0.
4.5.3 The transmitters are coupled with the secondary device with the use of a shielded four-wire cable. To enhance the transmitter immunity to industrial noise, it is good practice to use a shielded cable containing two twisted wire pairs.
4.5.4 The transmitters properly function provided that the coupling cable between the transmitters and the secondary devices is not longer than 1.5 km. It is permissible to use shielded test cables possessing the following parameters: RCABLE ≤100 Ω, CCABLE ≤0.1 μF and LCABLE ≤2 mH.
4.5.5 The data exchange between the transmitters and the secondary device is effected by the serial code in the asynchronous half-duplex mode through the internal protocol of the "Albatros" JSC. The rate of transmission is dictated by positions of switches on printed circuit boards of the transmitters and constitutes 1,200 bit/s, 2,400 bit/s or 4,800 bit/s. The rate of exchange is established to be equal to 4,800 bit/s by default.
5 Overall Dimensions
Figures II.4.1 shows overall dimensions of the DTM2 transmitters.
Figure II.4.1 − Overall Dimensions of DTM2 Transmitters |
