Flowserve 3400IQ Digital Positioner User Manual
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Logix 3400IQ Digital Positioner FCD LGENIM3401-00 – 06/06
flowserve.com
Writing	a	zero	to	integral	gain	(IGAIN)	will	clear	the	integral	summer.	The	integral	gain	can	then	be	
returned	to	its	original	value.
Inner loop offset (IL_OFFSET):	Three	control	numbers	are	summed	to	drive	the	inner	loop	spool	
position	control:	proportional	gain,	integral	summer,	and	inner-loop	offset.
Inner-loop	offset	is	the	parameter	that	holds	the	spool	in	the	‘null’	or	‘balance’	position	with	a	control	
deviation	of	zero.	This	value	is	written	by	the	positioner	during	stroke	calibration	and	is	a	function	of	
the	mechanical	and	electrical	spool	sensing	tolerances.	However,	if	it	becomes	necessary	to	replace	
the	driver	module	assembly	or	the	software	RESET	calibration	constants	has	been	performed,	it	may	
be	necessary	to	adjust	this	value.	The	method	below	should	be	used	to	adjust	inner-loop	offset.
Or simply perform a new stroke calibration.
From the fieldbus configurator:
• Set transducer block to OOS
• Enable Diagnostic Variable access in TEST_MODE
• Send a 50 percent command.
• Set integral to zero.
• Locate the DAC_PERCENT
• Write this percentage value to IL_OFFSET
• Write original value to Integral
These	tuning	sets	can	be	used	to	obtain	initial	values	for	Flowserve	products	and	comparable	
actuator	sizes.	The	user	may	need	to	adjust	this	tuning	to	achieve	optimal	performance	for	a	
particular	application.
Table VIII: Factory Tuning Sets
Mfg.
Tuning Set
GAIN_
LOWER
GAIN_
UPPER
GAIN_
MULT
lgain
Comparable
Size (in
2
)
Valtek
VFactory_A
1.0
2.0
0.05
10
25
VFactory_B
1.0
2.5
0.05
10
50
VFactory_C
2.0
3.0
0.05
10
100
VFactory_D
4.0
5.0
0.05
10
200
VFactory_E
4.0
7.0
0.05
10
300
Trooper 48
0.4
0.5
0.05
25
31
Trooper 49
3.0
4.0
0.05
10
77.5
Kammer
Trooper 48
0.4
0.5
0.05
25
31
Trooper 49
3.0
4.0
0.05
10
77.5
Automax
R1
0.3
0.5
0.05
10
3 to 5
R2
1.0
1.5
0.05
10
9 to 12
R3
1.3
2.0
0.05
10
16 to 19
R4
2.0
2.5
0.05
10
27 to 37
R5
2.5
3.6
0.05
10
48 to 75
R6
4.0
5.0
0.05
10
109
