IRIS P522 manual Redundant Power Supplies, Factory Stocked Power Supplies

IRIS MODEL P522 APPLICATION MANUAL

prevent the power from feeding into the 24 VDC supply. Each P522 module draws approximately 150 mA, and each viewing head draws about 100 mA of power (26 VDC). Actually, the S506 and S511 view- ing heads use less current, but it is a good idea to figure 100 mA for each viewing head used. Also, the amount of current drawn by the P522 will de- pend upon other factors that can affect the peak cur- rent, such as whether or not there is flame being de- tected, the remote meter output is connected, and se- rial communication is occurring.

The viewing head is powered through the P522 via a

0.25A self-resetting fuse. In other words, the 26 VDC power feeds into the P522 (through a 0.75 A self-resetting fuse) and feeds back out through a 250 mA fuse to the viewing head, resulting in a current drain of about 0.25 A for each P522 (with one view- ing head). This small amount of current means that one power supply could support a number of P522 modules. The self-resetting fuses change to high re- sistance when their current ratings are exceeded, but recover to their normal low resistance when power is removed.

with one viewing head each. And the 100-watt power supply will support up to fifteen P522 modules with one viewing head per each 100 watt. These “switch- ing type” power supplies are efficient and very com- pact. To obtain the size and weight of the power supplies, contact IRIS Systems Inc.

Each power supply can be either rail mounted or panel mounted, and it is up to each end user to deter- mine their installation preferences and requirements.

We recommend that not more than four P522 signal pro- cessors be supported by one 26 VDC power supply. For instance, four P522 processors with one viewing head each equals a total of 26 watts – a relatively small power supply, particularly if an efficient, switching type is used.

Other possible combinations can be used; for in- stance, the battery backup terminal could be used for redundancy. However, care must be taken with these redundant schemes to make sure that failure of the primary power supply won’t affect the backup power supply, as well.

						REDUNDANT POWER SUPPLIES
						It may be more economical to use larger-capacity
IRIS MODEL P522 POWER SUPPLY CAPACITY IN WATTS
						power supplies for applications using 12 or more
QTY	7.5W	15W	30W	50W	100W
						P522 signal processors.
1		X	X	X	X
						For example: the 100-watt power supply
2			X	X	X
						available from the factory can handle
3			X	X	X
						twelve P522 modules, each with one view-
4				X	X
						ing head. Should the power supply fail, a
5					X
						redundant scheme utilizing two power
6					X
						supplies with “steering” rectifiers to pre-
7					X
						vent current from flowing into a failed
8					X
						power supply output would prevent the 12
9					X
						flame monitors from being de-energized.
10					X	The positive output from each power supply is wired
FIGURE 4 - POWER SUPPLY TABLE
						to the anodes of the MBR 1545CT. This dual,
FACTORY STOCKED POWER SUPPLIES						Schottky-type rectifier, rated for 15 Amps, will present
						a low forward voltage drop for this application. Both
Power supplies are readily available from the fac-
						power supplies can be adjusted for 26V output, and a
tory for the P522 modules. The 30-watt power sup-						low-voltage indicator light can be used on the output
ply will support up to six or seven P522 modules						of each power supply to monitor their outputs.
with one viewing head each. The 50-watt power						Larger power supplies can be used with this redun-
supply will power up to six or seven P522 modules
						dant wiring scheme if there are more than twelve P522

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