THERMAL ENERGY METER MC 108/ET

Transcription

1 USCITE CONTATORE DI CALORE CONVERTITORE SENSORE ELETTROMAGN. EUROMAG CONTATORE DI ENERGIA TERMICA PORTATA: SENSORE ELETTROMAGN. uscite: TEMPERATURE: Pt ma potenza termica 4-20 ma temperatura ta impulsi (1 per KWh) ALIMENTAZIONE... impulsi (1 per mc) TEMP. AMBIENTE: -20 C C GRADO DI PROTEZIONE : IP 67 n. matr... 1/7 THERMAL ENERGY METER MC 108/ET The temperature of thermal energy transported in a liquid vector traditionally needs a flow meter, two temperature sensors and a calculation unit. Diagram 1 represents a simple diagram of the meter described in this brochure. The EUROMAG INTERNATIONAL solution foresees the use of a flow meter with magnetic induction coupled with an MC 108/ET converter plus two RTD. This system permits measurements, with a single electronic, the thermal power and/or the thermal energy transported by the liquid beyond its range. The MC108/ET converter is a special version of the MC108 converter normally manufactured by EUROMAG INTERNATIONAL, from which it differs in the added circuits of conditioning, the two RTD Pt 100 and the programme for measuring the thermal energy (diagram 2). The MC108/ET converters can be coupled with any full board sensor manufactured by EUROMAG INTERNATIONAL (table 1) according to the foreseen flow. LA VECCHIA SOLUZIONE Diagram 1. MC 108/ET E C 4-20 ma potenza termica (KW) 4-20 ma temperatura At energia termica (KWh) volume (mc) ALLARMI RS 485 SENSORE ELETTROMAGN. Pt 100 Diagram 2.

2 2/7 1. CASE AND ASSEMBLY The MC108/ET converters are cased in die-cast Aluminium with an IP 67 rate of protection. Access to the box terminal board and the fuses is possible simply by removing the relative inspection cover on which all data is indicated. On the front of the apparatus there is an LCD 2 line x 16 character display (eventually with back lighting) and a 6 key keyboard provided with software key and, on request, a sealed cover. Also on request the MC108 converter can be supplied blind, that is, without display and keyboard. Both the compact and separate versions are available for assembly. In the compact version the MC108/ET converter can be installed in the vertical position independent of the position of the sensor. 2. ON/OFF OUTPUT The standard version of the MC108/ET converter has three ON/OFF outputs; the first is for the signal with a frequency proportional to the range or the impulses of totalization, the second for programming alarms, the third for hardware alarms. The first and second ON/OFF outputs permit the choice of connection of the load to the collector or to the emitter so as to adapt the converter to any type of receiver (electromagnetic, electronic, CMOS, TTL, etc.) and to any continuous external power supply inferior to 40 Vdc ( 40 Vdc ) or to internal at 24 Vdc. Only the hardware alarm output is an open collector, in which case the load is connected between converter and the positive clamp (+) of the output of the internal 24V. Protection is also foreseen for the output in the case of: momentary over-voltage (zener intervention), inversion of polarity (I CC 1A), short circuit for an unlimited period in the case of internal supply. Should an external power supply be used for the ON/OFF outputs, this MUST BE CONTINUOUS AND MUST NOT EXCEED 40 Vdc. Each output is able to pilot a maximum power supply of 100mA. In the case of internal power supply of 24 Vdc, its MAXIMUM RECEPTIVENESS IS 100 ma, and consequently the maximum supply deliverable from an output depends on how many ON/OFF outputs are used contemporaneously; the additional modules must be taken into account. 3. OUTPUT 4(0) 20 ma This output permits the flow signal or the thermal power (client s choice) to be transported to a distance of up to 1 Km via a shielded two-wire cable, the maximum load permitted being 1000 Ohm. This output can also supply information in conformity with the NAMUR NE 43 regulation regarding any possible faults in the meter or malfunctions in the process. On request, a second output 4-20 ma for the transmission of the signal of a temperature can be provided 4. INTERFACE RS485 This is an insulated interface found both on the terminal board and on the DIN socket. It permits the connection of up to 32 flow meters on the network. In the case of blind measurers, without display, the interface RS485 permits, via the DIN outlet, connection to the remote control TRM100, visualization of data and predisposition of the necessary parameters for correct functioning of the measurers. The RS485 Interface permits also connection to flow meters with the remote terminal TRM200 which can be installed at a distance of 1500 m. With this remote terminal the flow rate can be visualised at a distance and it is also possible to programme at a distance. 5. DIGITAL INPUT This input can be used in three different modes: to reset the counters, to stop them, or to choose the measurement scale. There are two types of protection: a) for momentary over-voltage (200 Vdc MAX per 1 ms, duty cycle 1%) b) polarity inversion for unlimited time (Vin max =32 Vdc or 200 max V dc per 1 ms, duty cycle 1%) 6. INPUT FOR THERMAL RESISTENCE Within the case of the MC108/ET converter a 4 wire module with two inputs for thermal resistance Pt100 for measuring the temperature in the tubes both transmitting and receiving is installed.

3 EUROMAG CONTATORE DI ENERGIA TERMICA uscite: PORTATA: SENSORE ELETTROMAGN. TEMPERATURE: Pt 100 ALIMENTAZIONE... TEMP. AMBIENTE: -20 C C GRADO DI PROTEZIONE : IP ma potenza termica 4-20 ma temperatura ta impulsi (1 per KWh) impulsi (1 per mc) n. matr... EUROMAG - ITALY E C 3/7 7. REMOTE TRANSMISION OF MEASURMENTS For remote transmission of measurements, two solutions, independent of the client s requirements, are possible. The first solution foresees a system similar to that shown in diagram 3. A TRM200 connected to the output RS485, placed at a distance maximum of 1500 meters, permits both readings of the measurements available on the MC108/ET converter and operation of all the presetting (full scale flow meter, temperature range, measurement unites, etc.). It should also be remembered that numerous flow meters equipped with as many MC108/ET can be connected in a single network capable of transmitting all measurements to a central unit (TRM 200, PC, PLC, etc.) MC 108/ET anche in esecuzione compatta distanza massima 1500 metri TRM 200 predisposizioni indicazioni uscite SENSORE ELETTROMAGN. Pt 100 Diagram 3. The second solution foresees only visualisation at a maximum distance of 1500 meters of the impulses emitted by the converter MC108/ET via the use of an electronic impulse counter connected to the impulse output as shown in diagram 4. Diagram 4.

4 4/7 8. FUNCTIONS The density of the water is given by equation supposing that the water is in such temperature and pressure conditions that it will never reach saturation point (steam development). The apparatus integrates with respect to time the thermal power and supplies an impulse every kwh (or its sub multiple). On the display it is possible to visualise (in unit S.I. or techniques chosen by the client): (1) water flow rate (2) water volume (3) inlet temperature (4) outlet temperature (5) thermal power (6) thermal energy (7) date and time The totalized values (energy and volume) as well as the date and time are memorized, even in case of an interruption of the mains power supply. 9. THERMO RESISTANCE The temperature of the inlet and the outlet are established via the RTD Pt 100 DIN 43760, selected in couples (max. error 0,1 C to 0 C). These RTD have 4 wires so that during measurement the influence of the cable length is completely eliminated. There are two standard models: 1) Model TRM-B , complete with a sump in AISI 316, of 5 mm diameter and 50 mm long under the connection. The fitting of the sensor pocket to the process is a 1/4" gas threaded joint. The RTD is also equipped with an IP 67 connector at 90 and 10 metres of 4 wire cable. 2) Model TRC-B for insertion directly in the process by means of a 1/8" threaded attachment gas UNI 338 and a connector at 90. Sensitive element in AISI 316 of 3 mm diameter and length 24 mm. The thermal element is equipped with a 4 contacts IP 67 connector. Diagram CALIBRATION Calibration of the instrument comprises calibration of the flow rate and of the two RTD s. For the first, a hydraulic bench equipped with an SIT certified balance can be used. The water measured by the magnetic flow meter ("measured volume") is weighed on the scales; from this weight the "true volume" can be obtained using the density value of test temperature. By means of digital operations on the instrument gain, one can make the measured volume coincide with the true volume. To calibrate the temperature measurement section, one can use sample resistances with values equal to those assumed by the PT 100 at the minimum and maximum temperatures of the operating range of the instrument. These values are supplied by DIN Standard tables. The values of the sample resistances are controlled by a HP A multi-meter. While awaiting to perform accurate tests in specialized laboratories, one can expect a global error of the thermal power in the order of 1.5% of the full scale working with an t of 20 C and a water velocity of 2-3m/s.

5 5/7 11. REFERENCE STANDARDS The apparatus is manufactured according to the following standards: CEI 66-5 (EN 61010/1) EN (electromagnetic compatibility - emission) EN (electromagnetic compatibility - immunity) IEC IEC EN CEI ENV EN ISO 6817 ISO NAMUR NE 43 The apparatus is made according to EC regulations. 12. NOTES ON MEASUREMENTS The equivalence between the principal measurements of thermal power and energy can be seen in Tables 2 and 3. Concerning this, the International System of units in force in Italy as of 1 January 1979 (Law of 14 April 1978 n. 122) foresees the use of watt and watt-hour and their multiples for thermal power and energy; the use of calories and their multiples is no more in force. COUPLING SENSORS MUT500 MUT501 MUT1000 MUT1100 MUT2200 MUT2400 MUT2500 MC108/ET : SEPARATE : COMPACT Table 1. W kw MW Btu/h kcal/h 1 W ,413 0, kw , , MW , , Btu/h 0,293 0, , , kcal/h 1,163 1, , ,968 1 Table 2 Thermal Power

6 6/7 Wh kwh MWh J Btu kcal 1 Wh , ,413 0, kwh , , , MWh , , , J 0, , , , , Btu 0,293 0, , , , kcal 1,163 1, , , ,968 1 Table 3 Thermal Energy GENERAL CHARACTERISTICS CHARACTERISTICS AND PERFORMANCE MC108 HV MC108 LV Display with 2 lines of 16 characters Keyboard Output power supply 4(0) - 20 ma [3] Second output power supply 4(0) - 20 ma [3][4] [4] [4] Output Imp./ freq. 24 Vdc for impulses thermal energy [5] Second output on/off 24 Vdc impulses water flow [5] Third output on/off 24 Vdc (hardware alarms) [5] Interface RS 485 Entrance for TRM 100 Network connection (RS 485) Entrance Reset totalizers Entrance for two RTD Pt 100 with 4 wires Velocity of communication: baud Auto-ranging Metric system: Decimal, English, American Message languages: Italian or English Power: 3 10 W [5] Installation: Separate or Compact [6]. Degree of protection IP67 Working environmental temperature -20 C a + 60 C Weight converter: 4000 g Electric power supply (high tension): Vac, Hz. Electric power supply (low tension): Vac, Hz, Vdc. [3] Maximum load 1000 Ohm. This second output is optional on request [5] Overall delivery of the two outputs ON/OFF max 100 ma [6] Depends on the diameter of the sensor. [7] The maximum length of the cable is 10 m. Table 4.

7 7/7 OVERALL DIMENSIONS Dimensions and weight of MC308 Length Height Depth Weight MC108/ET mm mm mm 4000 g Diagram 6 Table E C FORI FORI 0 6 Diagram The data shown in this manual are subject to modification without prior notice.