Data Sheet

3610J and 3620J Positioners
D200064X012
Product Bulletin
62.1:3610
February 2015
10
Figure 6. Input Span Versus Valve Rotation
DEGREES OF VALVE ROTATION
DIRECT
REVERSE
PERCENT OF RATED INPUT SPAN
CAM
B
CAM
A
A2264-1
CAM
C
Figure 7. Flow Characteristics for the Various Cams
When Used with an Equal Percentage Characteristic,
Push-Down-to-Close Valve
DIRECT
REVERSE
PERCENT OF RATED INPUT SPAN
CAM
B
CAM
A
CAM
C
33A4960-A
A1582-2
PERCENT OF FLOW
(PRESSURE DROP CONSTANT)
PUSH DOWN TO CLOSE
Characterized Cams
3610J and 3620J positioners are available with any one
of three cams, a linear cam (cam A) or two
characterized cams (cams B and C). Figure 6 shows the
resultant valve rotation due to an incremental
instrument pressure change for the three cams.
Figures 7 and 8 show how the flow characteristics
change when using the cams with a valve that has
equal percentage characteristics.
Figure 8. Flow Characteristics for the Various Cams
When Used with an Equal Percentage Characteristic,
Push-Down-to-Open Valve
DIRECT
REVERSE
PERCENT OF RATED INPUT SPAN
CAM
B
CAM
A
CAM
C
PERCENT OF FLOW
(PRESSURE DROP CONSTANT)
PUSH DOWN TO OPEN
33A4959-A
A1581-2
When the linear cam is the operating cam, there is a
linear relationship between an incremental instrument
pressure change and the resultant valve stem rotation.
The flow characteristic is that of the control valve.
As shown in figure 6, installing either characterized
cam as the operating cam changes the relationship
between the incremental instrument pressure change
and valve stem travel, thereby modifying the valve
flow characteristics.
Ordering Information
When ordering, specify the product application and
construction:
Application
1. Positioner type number
2. Maximum supply pressure available
3. Actuator size and type number
4. Cam characteristic
5. Input signal
Construction
Refer to the specifications. Carefully review each
specification; indicate your choice whenever a
selection is to be made.