IRIS P522 manual Adjusting Set Points, PLICATION TABLES are, Gain potentiometers POTS full

IRIS MODEL P522 APPLICATION MANUAL

The above settings will be satisfactory for most applications, but are used only as a starting point. So many variables can affect the readings that it is impossible to catalogue all the settings, and each viewing head has its own characteristics for the different types of fuels and burn- ers. We recommend that you become knowledgeable about the characteristics of the different viewing head models available before applying them to a par- ticular application. Detailed descriptions of the viewing heads are provided in this manual, and the VIEWING HEAD AP-

There must be a definitive ratio between the read- ings for burner ON and burner OFF. This ratio can be defined by using the lowest reading for burner ON from both of the load conditions, and the high- est reading for burner OFF from both of the load conditions. If the readings are 2:1 or more (BNR ON to BNR OFF) then there should be no problem discriminating between burners.

A good balance for the set points would be:

ON SET POINT = .75A + .25B

OFF SET POINT = .25A + .75B

PLICATION TABLES (Figure 11) are	where A is the lowest burner ON reading, and B is
a useful summary of the viewing heads	the highest burner OFF reading.
and their response to different fuels.	Actually, a smaller ratio will work, as long as the
B. The initial settings for the flicker type
	lowest BNR ON reading and the highest BNR OFF
viewing heads (S509, S511, S512) should	reading never deteriorates to the point the former is
be as follows:	equal to or less than the latter. In other words, A
1. Set filter switch to LL position.	must always be greater than B. Using a safety factor
	of 2:1 will allow for flame signal changes that prob-
2. Gain potentiometers (POTS) full	ably will occur over a period of time.
clockwise (these are 25-turn potenti-	A. FOR FLICKER TYPE VIEWING
ometers – a slight clicking sound will
	HEADS: If unable to achieve discrimi-
be heard when the POT is maximum
	nation from background signals (for mod-
clockwise). There are two POTS on
	els S509, S511 and S512 viewing heads),
the S509: one for the Si channel, and
	remove the viewing head housing from
one for the PbS channel. If the fuel is
	the flange and place the filter switch to
natural gas, turn the Si channel off
	the next highest position L. Reinstall the
(POT full counter clockwise). Refer
	viewing head and take another set of read-
to section S509 VIEW HEAD.
	ings. Note: the filter switch should be
C. There are no initial settings for the S506	moved only one position at a time for
UV viewing head. It is important that	each set of readings. Refer to section
this viewing head be properly aimed to	MULTIBURNER REQUIREMENTS.
pick up the maximum signal, as described	B. FOR THE S509 VIEWING HEAD: If
in the previous section.
	you are still unable to achieve satisfac-
ADJUSTING SET POINTS	tory flame OFF operation, remove the
Before adjusting the set points, take readings with	viewing head and turn the Si channel off
	by turning the Si POT at least 30 turns
the P522 on the two worst-case conditions described
	counter clockwise. The signal level will
(see section SETUP AND ADJUSTMENT PRO-
	now be lower because only the PbS de-
CEDURES). Write down the readings for the burner
	tector is being used, so the set points must
ON and OFF (with other burners on) under low load
	be re-evaluated. If you are using an S511
conditions, and then the readings for the burner ON
	viewing head and not achieving success-
and OFF under high load conditions.
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