Intrinsically Safe
Interface Solutions: These are typical system diagrams using Isolation interfaces for E2S Intrinsically safe sounders and beacons. Please contact E2S for further information. |
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The basic installation is straightforward on/off control using a zener barrier with entity parameters 28v 93mA (often referred to as 28v 300Ω) which is an industry standard barrier (Power driver). |
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To simplify drawings the rest of the illustration do not show the representative voltage clamping diode. |
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Similarly another diode return can be added for the 3 rd stage audible alarm |
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The sounder and beacon IS-mC1 or the combination of IS-105N and IS-L101 can be powered from a single zener barrier. Similarly an IS-mA1 plus IS-mb1 could be run from a single zener barrier |
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For independent control use a double channel Zener barrier. |
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Again with the option of 2nd tone switch. This can be extended further using 2 power and diode returns zener barriers to switch the 3rd alarm tone (not shown). |
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The combined IS-A105N / IS-L101L has a mute option, adding a switch will mute the alarm |
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However many DCS cards use pull down signals such as open collector, common emitter outputs. Then a common power feed would be used with all switching being done via a diode return barrier |
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Adding another diode return gives a second stage alarm. |
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Zener Barriers
| Any interface with parameters | ||
| Uo ≤ 28v | I o ≤ 93mA | P o ≤ 660mW |
| or for the Diode return channel | ||
| Uo ≤ 28v | I o ≤ 0mA | |
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Single Power |
Double Power |
Power Plus Diode Return |
Double Diode Return |
Power + 2x Diode Return |
Triple Diode Return |
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Pepperl & Fuchs |
Z728 |
Z779 |
Z787 or Z787F |
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Z789 |
Z786 |
MTL |
7728+ or 7706+ |
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7787+ or 7707+ |
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7789+ |
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Stahl |
9001/01-280-085-101 |
9002/11-280-186-001 |
9002/13-280-093-001 |
9002/33-280-000-001 |
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Should you manufacture a suitable Intrinsically safe interface or wish to comment on these applications please email sales@e2s.com
Further Reading:
| EN1127-1 | Explosive atmospheres: Explosion prevention and protection | |
| Part 1: | Basic concepts and methodology | |
| EN 60079 | ELECTRICAL APPARATUS FOR EXPLOSIVE GAS ATMOSPHERES | |
| Part 0 | General requirements | |
| Part 14 | Installation (and selection) of equipment in hazardous areas | |
| Part 25 | Intrinsically safe systems | |
Suggested reference book on intrinsic safety and hazardous areas
Electrical Apparatus and Hazardous Areas by Robin Garside. 5th Edition 2007
ISBN 978-0-9516848-4-9
Next....
►Introduction
►Interface
selection
►Zener
barriers
►Isolation
interfaces
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