User manual VAISALA HMT360

[. . . ] USER'S GUIDE Vaisala HUMICAP® Dewpoint and Temperature Transmitter Series HMT360 M210744EN-C PUBLISHED BY Vaisala Oyj P. O. Box 26 FIN-00421 Helsinki Finland Phone (int. ): Fax: +358 9 8949 1 +358 9 8949 2227 Visit our Internet pages at http://www. vaisala. com/ © Vaisala 2010 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice. Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user. [. . . ] Examples of connections and more information on installation in hazardous locations is given in section Examples of Connections on page 41. VAISALA _______________________________________________________________________ 35 User's Guide ______________________________________________________________________ Installation in Hazardous Locations US and Canadian Requirements USA (FM): Wiring for intrinsically safe operation is shown in Appendix B, Wiring for Intrinsically Safe Operation, FM, on page 87. Canada (CSA): Wiring for intrinsically safe operation is shown in Appendix C, Wiring for Intrinsically Safe Operation, CSA, on page 89. European Requirements CATEGORY 1 (Zone 0) HMT360 has to be connected to Exia-certified associated apparatus with galvanic isolation, gas group IIB or IIC. NOTE If both analog outputs are in use, the Ch 1 (-) and Ch 2 (-) must be short circuited (see Figure 18 on page 41). CATEGORY 2 or 3 (Zone 1 or 2) HMT360 has to be connected either to a Zener barrier or galvanic isolator NOTE If both analog outputs are in use with a galvanic isolator, the Ch 1 (-) and Ch 2 (-) must be short circuited (see Figure 18 on page 41). Figure 16 on page 39 and Figure 17 on page 40 present examples of galvanic isolators and Zener barrier connections (only Ch 1 connected). 36 __________________________________________________________________ M210744EN-C Chapter 3 _______________________________________________________________ Installation Maximum Cable Resistance Calculation for the Barrier (Vaisala Order Code: 210664) General specifications of HMT360: Supply voltage Maximum current Minimum operating voltage for HMT360 Uin = 24 V (12 . . . 35 V) Iout = 20 mA Umin = 12 V (15 V with serial port) Stahl 9001/51-280-091-141 (values taken from the specifications): Rated operating voltage Transmitter supply voltage UN = 20 . . . 35 V US = UN - 9. 5 V, when UN 23. 5 V or US = 14 V, when UN 23. 5 V RL 350 Maximum load Calculation of the maximum cable length from barrier to transmitter: Cable resistance (as an example) Rcable = 0. 085 /m/core (2 × 0. 085 /m/pair) If assuming that the operating voltage would be 24 V, the maximum acceptable voltage drop Udrop in cables is: Udrop = US - Umin Udrop = 14 V - 12 V = 2 V We also know that: Iout = 20 mA and that total resistance of the cable Rcabletot is cable resistance Rcable multiplied with the total maximum length of the cables lmax: Rcabletot = Rcable × lmax VAISALA _______________________________________________________________________ 37 User's Guide ______________________________________________________________________ From these facts the following equation can be formed: Udrop = Rcabletot × Iout 2 = 2 × 0. 085 /m × lmax × 20 mA lmax = 2 V / (20 mA × 2 × 0. 085 /m) lmax = 588 m = 1930 ft, maximum cable length. NOTE If longer cable length is required, use of the galvanic isolators is recommended if possible. HMT360 Connected to a Galvanic Isolator HAZARDOUS AREA SAFE AREA I a) current signal controller 0505-278 38 __________________________________________________________________ M210744EN-C Chapter 3 _______________________________________________________________ Installation HAZARDOUS AREA SAFE AREA b) voltage signal controller 0505-279 Figure 16 HMT360 Connected to Galvanic Isolator HMT360 Connected to a Zener Barrier HAZARDOUS AREA SAFE AREA a) current signal controller 0505-280 VAISALA _______________________________________________________________________ 39 User's Guide ______________________________________________________________________ 0505-281 Figure 17 HMT360 Connected to a Zener Barrier 40 __________________________________________________________________ M210744EN-C Chapter 3 _______________________________________________________________ Installation Examples of Connections 0505-282 Figure 18 STAHL 9160/13-11-11 (Galvanic Isolator) VAISALA _______________________________________________________________________ 41 User's Guide ______________________________________________________________________ 0505-283 Figure 19 STAHL 9001/51-280-091-141 (Zener Barrier) Grounding When grounding the transmitter, follow the local requirements. Use at least 4 mm2 grounding cable when grounding the transmitter or barrier. Note that the allowed resistance between barrier and system ground must be less than 1 ohm. Use ground terminal located inside or outside of transmitter Figure 20 on page 43: 42 __________________________________________________________________ M210744EN-C Chapter 3 _______________________________________________________________ Installation HAZARDOUS AREA SAFE AREA 0505-284 Figure 20 Grounding VAISALA _______________________________________________________________________ 43 User's Guide ______________________________________________________________________ 44 __________________________________________________________________ M210744EN-C Chapter 4 ________________________________________________________________ Operation CHAPTER 4 OPERATION This chapter contains information that is needed to operate this product. Local Interface HMT360 transmitter has four pushbuttons located on the housing cover. The display/keypad commands (see Display/Keypad Commands on page 48) can be used to scale the outputs and select output quantities. The measurement results are shown on the display. The keypad pushbuttons are indicated (from left to right) as C, Up, Dn, and E (see Figure 21 on page 46): VAISALA _______________________________________________________________________ 45 User's Guide ______________________________________________________________________ 0606-155 Figure 21 Local Display/Keypad Interface Power ON/OFF Open the transmitter cover and flip the internal power switch to position ON (up), see Figure 23 on page 64. When the transmitter is turned on, the existing pressure setting appears on the display; the default setting is 1 bara (15 psia). After this, measurement readings appear on the display. The analog output signals can be read from the system or load resistor. WARNING Avoid static discharge. Always use a wet cloth for wiping the display. To modify the pressure setting, turn the internal Calibration Enabled/ Disabled DIP switch of the transmitter to position Enabled (up). Adjust the pressure reading with buttons Up and Dn on the display cover; the adjustment step is 0. 5 bara). To complete the pressure setting, turn the DIP switch back to position disabled (down). If the pressure setting is not modified, the measurement readings appear automatically on the display after 60 seconds. 46 __________________________________________________________________ M210744EN-C Chapter 4 ________________________________________________________________ Operation DIP Switch Functions The table below is also printed on the protection board: 0505-285 Figure 22 DIP Switch Functions 1: Analog output test on/off If you turn the switch to on position (up), you can force the outputs to states 4 mA, 12 mA and 20 mA by pressing buttons Up and Dn on the cover. Outputs return to normal mode when switch is turned down. 2: Calibration Disabled/Enabled The EEPROMs are write protected. [. . . ] Gently dehydrate the sensor with dry gas (nitrogen) if available. When the sensor and probe are both dry, install the filter back to the probe. CAUTION Do not touch the sensor surface. Only de-ionized water or IPA is allowed, other agents such as ethanol cannot be used. Do not immerse the sensor in water or IPA for more than one minute. [. . . ]