Worcester Controls
MODELS
20 – For AF-17 Boards Mounted Inside 10-23 75 Actuator.
30 – For AF-17 Boards Mounted Inside 25-30 75 Actuator.
AF-17-1K, 120A or 240A, 1000 ohm Resistance Input
AF-17-13, 120A or 240A, 135 ohm Resistance Input
AF-17-1, 120A or 240A, 1 to 5 Milliamp Input
AF-17-4, 120A or 240A, 4 to 20 Milliamp Input
AF-17-10, 120A or 240A, 10 to 50 Milliamp Input
AF-17-5V, 120A or 240A, 0 to 5 VDC Input
AF-17-XV, 120A or 240A, 0 to 10 VDC Input
R – Reverse Action Option
120A-120 VAC Power Circuits
240A-240 VAC Power Circuits
WCAIM2031
AF-17 Electronic Positioner
Installation, Operation and Maintenance Instructions
2 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
1.0 GENERAL 3
1.1 Basic Design 3
1.2 Environmental Considerations 4
1.2.1 Temperature 4
1.2.2 Positioner Temperature 4
1.2.3 Humidity 4
1.2.4 Input Circuit Noise Protection 4
2.0 ELECTRONIC CIRCUIT BOARD 6
2.1 General 6
2.2 Circuit Board Configurations 6
2.3 LED Indicators 6
2.4 Controls 6
2.4.1 Range 6
2.4.2 Zero 6
2.4.3 A-H 6
2.5 AC Power Control 6
3.0 INSTALLATION OF AF-17 INTO
3.0 SERIES 75 ELECTRIC ACTUATOR 7
3.1 General 7
3.1.1 Check Kit for Parts 7
3.1.2 Tools Needed 8
3.1.3 Operation Check of Basic Actuator 8
3.2 Mounting Potentiometer 8
3.2.1 Mounting Single
Potentiometer Into
Series 75 Electric Actuator 8
3.2.2 Mounting Dual
Potentiometer Into
Series 75 Electric Actuator 8
3.2.3 Potentiometer Wiring 8
3.2.4 Adjusting Potentiometer 9
3.2.5 Important Note 9
3.3 Mounting Circuit Board 11
3.3.1 For 120/240 VAC 10-23 Size Electric Actuators 11
3.3.2 For 120/240 VAC 25 and 30 Size Electric Actuators 12
3.3.3 For Optional 4-20 mA Position Output Installation 12
3.4 Wiring AF-17 Board to Actuator 13
3.4.1 Terminal Strip 13
3.4.2 Feedback Connections 14
3.4.3 Output Connections 14
3.4.4 For 10-30 AF-17 240 VAC Positioner Wiring 14
3.4.5 Wiring for AF-17 with 4-20 mA Position Output 14
3.5 Actuator Power 15
3.5.1 Wire Size 15
3.5.2 Terminations and Voltage 15
3.5.3 Minimum Fuse Ratings 15
3.6 Input Signal Connections 16
3.6.1 Milliampere 15
3.6.2 Resistive 16
3.6.3 Direct 17
4.0 CALIBRATION AND ADJUSTMENT 17
4.1 Initial Setup and Adjustment 17
4.2 Zero Adjustment 17
4.3 Range Adjustment 17
4.4 AH Adjustment 17
4.5 Adjustment Recheck 18
4.6 Operational Check 18
4.6.1 Increasing Signal 18
4.6.2 Decreasing Signal 18
4.6.3 Attaching Label 18
4.7 If Problems Occur 18
4.7.1 Cam Adjustment 18
4.7.2 Feedback Pot Calibration 18
4.7.3 Reverse Acting 18
4.7.4 Adjustment to Loop Process 18
4.7.5 Check Fuse F1 19
4.7.6 Check Basic Actuator for Proper Operation 19
4.7.7 Check for Noise Problems 19
4.7.8 Replace Circuit Board 19
5.0 OPERATIONAL VARIABLES 19
5.1 Sensitivity 19
5.2 Reduced Travel Operation 19
5.3 Split Range 19
5.4 Reverse Action 19
5.4.1 Milliampere Input 20
5.4.2 Resistive Input 20
5.4.3 Voltage Input 20
5.4.4 240 VAC 20
6.0 TECHNICAL DATA 20
6.1 AC Input Voltage 20
6.2 Input Circuit Specs 20
6.3 Output Circuit Specs 21
6.4 Input Circuit Characteristics 21
6.4.1 Input Circuit Load Resistances 21
6.4.2 Nominal Useable Input Signal Deadband 21
6.5 Controls 21
7.0 APPLICATION NOTES 22
7.1 DC Motor Actuator 22
7.2 Bypass Switch for Manual Control 22
8.0 TROUBLESHOOTING 23
8.1 General 23
8.2 Symptom Table 24
8.3 Troubleshooting Guidelines 25
9.0 SUGGESTED SPARES 27
Flow Control Division
Worcester Controls
TABLE OF CONTENTS
WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 3
1.0 GENERAL
1.1 Basic Design
The Worcester AF-17 Electronic Positioner was designed for use with the Worcester Series 75 actuators. However, it may also be
used with other actuators or electrically operated rotary devices, provided the specified load parameters as given in Part 6.3 are
not exceeded.
CAUTION: This positioner is sensitive to electrical noise; please see part 1.2.
PLEASE READ THIS SECTION
A. The AC AF-17 board 4-20 mA signal input circuit is protected with a 62 mA fuse (F1). The fuse is used to protect the input
circuit from an excessively high voltage. The fuse used in the input circuit is a Littlefuse PICO II very fast-acting fuse rated at 62
mA. There is a spare fuse located on the circuit board in the area of the large power resistors.
B. The AF-17 board is designed to receive a floating current input signal. This allows several pieces of equipment to be operated
from the same current loop while at the same time remaining electrically independent of each other.
C. The AF-17 board can be set up in several ways for normal operation. The board is designed to control in 90° quadrants only.
The number of quadrants over which the board will control is determined by the number of teeth on the feedback pot pinion
gear. The adjustment trimpots on the board were not set up to reduce actuator travel for a 4-20 mA input span. For example,
trying to adjust the board such that 4 mA is closed and 20 mA is only 60% open is not possible with the standard set up.
The standard setups are:
1. 4 mA for full clockwise rotation, i.e., 0°, and 20 mA for full counter-clockwise rotation, i.e., 90° or 180°.
2. Split range where 4 mA would be full clockwise and 12 mA would be full counter-clockwise or 12 mA would be full clockwise
and 20 mA would be full counter-clockwise.
3. Each of the above standard setups can also be made reverse-acting.
Standard 90° Actuator 180° Center-Off Actuator
Series 75W, X, and Z Shown Series 75W, X, and Z Shown typical
D. Quite often when we receive an actuator for repair at Flowserve we find that the only thing wrong with the unit is that the
feedback potentiometer is out of calibration. It is very important that the feedback pot be properly calibrated for correct
operation of the positioner board. It is also very important that the actuator shaft not be rotated out of the quadrant for which
the feedback pot has been calibrated. Whenever you have a problem with the positioner calibration, always check the feedback
pot calibration first. This must be done with no power applied to the circuit board. If the actuator is in the full clockwise
position, check the resistance between the purple and white/black potentiometer leads. The reading should be 80-90 ohms. If it
is not, rotate the face gear until the proper reading is achieved. If the actuator happens to be in the full counter-clockwise
position then check the resistance between the green and white/black potentiometer leads. If necessary, adjust the face gear for
an 80-90 ohm reading. NOTE: It is not
necessary to loosen or remove face gear snap ring(s) to rotate gear; it is a friction fit.
Flow Control Division
Worcester Controls
Quadrants of Operation
4 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
1.2 Environmental Considerations
CAUTION: The AF-17 Electronic Positioner is sensitive to electrical noise on signal or supply lines and in the environment.
For maximum sensitivity, the electrical noise level should not exceed 10mV. Follow installation, calibration and adjustment
guidelines carefully and use shielded wire as stated in paragraph 1.2.4.
Flowserve recommends that all products that must be stored prior to installation be stored indoors, in an environment
suitable for human occupancy. Do not store product in areas where exposure to relative humidity above 85%, acid or alkali
fumes, radiation above normal background, ultraviolet light, or temperatures above 120°F or below 40°F may occur. Do not
store within 50 feet of any source of ozone.
Temperature and humidity are the two most important factors that determine the usefulness and life of electronic equipment.
1.2.1 Temperature
Operating solid-state electronic equipment near or beyond its high temperature ratings is the primary cause for most
failures. It is, therefore, very important that the user be aware of and take into consideration, factors that affect the
temperature at which the electronic circuits will operate.
Operating an electronic device at or below its low temperature rating generally results in a unit operating poorly or not at all,
but it will usually resume normal operation as soon as rated operating temperatures are reached. Low temperature
problems can be easily cured by addition of a thermostatically controlled heater to the unit’s housing.
At high temperatures, some components will destruct completely when their maximum temperature is exceeded; others will
cease operation at temperatures above ratings and will return to operation at normal ratings, but may have been
permanently changed in one or another parameter, causing a device to operate poorly, and may also cause greatly reduced
component life.
1.2.2 Positioner Temperature Considerations
The Worcester AF-17 Electronic Positioner is rated for operation between -40°F and 160°F. When using the positioner inside
the Worcester 75 Series actuators, a maximum ambient temperature of 115°F is required to ensure the circuit board
maximum temperature of 160°F is not exceeded.
1.2.3 Humidity
Most electronic equipment has a reasonable degree of inherent humidity protection and additional protection is supplied by
the manufacturer, in the form of moisture proofing and fungicidal coatings.
Such protection, and the 3 to 4 watts of heat generated by the circuit board assembly will generally suffice for environments
where the average relative humidity is in the area of 80% or less and ambient temperatures are in the order of 70°F average
with only occasional short term exposure to temperatures up to 90°F. Where relative humidity is consistently 80 to 90% and
the ambient temperature is high or subject to large variations, consideration should be given to installing a heater and
thermostat option in the enclosure. The heater should not increase the enclosure temperature to the point where the circuit
board assembly’s temperature rating of 160°F is exceeded.
In those instances where the internal heater would bring the circuit board’s operating temperature near or above its
maximum rating, the user might consider purging the enclosure with a cool, dry gas. The initial costs can usually be paid
off quickly in the form of greatly extended equipment life, low maintenance needs, and much less process downtime.
1.2.4 Input Circuit Noise Protection
Shielded wiring should be used for all signal input circuit wiring regardless of length.
With separately housed positioners, the wiring from the feedback potentiometer to remote positioner, would be considered
as signal input wiring and should also be shielded wire.
The shields should never be used in place of one of the input wires, and the shields normally should be grounded to
equipment housings at one end of the wiring run only. Grounding both ends of shielding can eliminate the shielding benefits
because of current ground loops. If two or more shielded cables come to the positioner from different locations, ground the
shields at the positioner.
Flow Control Division
Worcester Controls
WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 5
Flow Control Division
Worcester Controls
Figure 1 – 120 VAC AND 240 VAC POSITIONER CIRCUIT BOARD
NOTES:
J1 and J2 with red and black wires are
on 240 VAC board only.
Use or values of components R13, R24,
R52, R53, R54, C22, J3, J4 and orange
wire will vary depending on input signal.
R5 and R7 used only for 25 and 30 size
actuators.
6 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
2.0 ELECTRONIC CIRCUIT BOARD (120/240 VAC)
2.1 General
Figure 1 defines the location of major components and wires from the positioner to terminal strip connections. The #18 gauge
white wire is the AC power unit “neutral” (or common) in the case of DC input wire. The #20 gauge white/black wire is one of the
connections between the feedback pot and the terminal block (TB-1) on the circuit board.
2.2 Circuit Board Configurations
The positioner board is factory supplied for one of the seven input signal options.
NOTE: Field changes to the positioner board are not advised. Consult Flowserve before attempting any modification.
2.3 LED Indicators
Light emitting diodes (LED) marked LD1, LD2 and LD3 are in the output circuits of amplifier U4. LD1 is tied to pin #13, LD2 to pin
#14, and LD3 to pin #1, and they are each associated with their respective opto-coupler U1, U2 and U3 and indicate when the
input side of the opto-coupler is energized.
2.4 Controls
Three adjustment potentiometers are provided, located on the top side of the board and marked “Range”, “Zero”, and “AH”. See
Figure 1.
2.4.1 Range
The “Range” Control adjusts the positioner’s feedback circuit to cover the same span of voltage as generated by the input
signal.
2.4.2 Zero
The “Zero” adjustment is basically an offset adjustment in that essentially all input signals start at other than a zero signal
condition, i.e., 1, 4 or 12 milliamps.
2.4.3 A-H
The “AH” Control is used primarily to balance the positioner to the dynamic characteristics of the device and media being
controlled. Functionally, it varies the amount of input signal that must be applied to the positioner to cause the actuator to
reverse its direction of rotation. In effect it varies the deadband of the positioner on a reversing signal condition only. The
deadband — the percent change in input signal change that must be applied to initiate a movement of the actuator — on a
signal that is constantly increasing or decreasing, is relatively unaffected by the “AH” control.
The “AH” control can vary the balance point deadband from approximately .3% to 4.0% of signal span. It can therefore be
used to help decrease the effects of signal noise, with a tradeoff in accuracy/sensitivity.
2.5 AC Power Control
The AC output circuits are controlled by solid-state switches (triacs Q1, Q2, Q3), which will provide trouble-free operation for the
life of the equipment they are used with, AS LONG AS THEY ARE OPERATED WITHIN THEIR RATINGS.
The ratings for the solid-state switches used in the Worcester AF-17 Positioner are listed in Part 6.3.
Flow Control Division
Worcester Controls
WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 7
3.0 INSTALLATION OF AF-17 INTO SERIES 75 ELECTRIC ACTUATOR
3.1 General
If the actuator was purchased with the AF-17 positioner board factory installed, proceed to section 4.0.
If a 4-20 mA Position Output option is also used with the AF-17 positioner, refer to paragraph 3.3.3 for installation (if not already
installed), and paragraph 3.4.5 for wiring.
3.1.1 Check Kit For Parts
A. Common Parts For Sizes 10-30 Actuators
Additional Parts For 10-23 Actuators:
Additional Parts For 25 and 30 Actuators:
Quantity Name
1 Pot Kit Subassembly
1 Mounting Bracket
2 Mounting Screw (Bracket)
Quantity Name
1 Pot Kit Subassembly
1 Bracket – Right (Long)
1 Bracket – Left (Short)
2 Spacer (Bracket)
2 Mounting Screw (Bracket/Spacer)
1 Support Bracket – Transformer
1 Spacer – Transformer Support Bracket
(for 23 Size Only)
Quantity Name
1 Circuit Board Subassembly
1 Insulating Board
5 or 6 Washers (Nylon)
5 or 6 Grommets (Rubber)
5 or 6 Mounting Screws (Circuit Board)
1 Nameplate – Circuit Board
1 Nameplate – Base
1Wiring Label – Cover
1 Instruction Manual
5 Cable Ties
2 Closed End Splice
1Wire – White
Flow Control Division
Worcester Controls
8 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
3.1.2. Tools Needed
1
/
4" nut driver,
1
/
8" screwdriver, needle nose pliers,
1
/
16" Allen wrench (cams and spur gear).
Volt/ohm meter (checking feedback potentiometer resistance, voltages – incoming process signal).
Milliamp source (to check calibration of positioner on actuator).
VAC line cord (to power basic actuator).
3.1.3. Operation Check of Basic Actuator
Set cams for about 1° to 3° of over travel in each direction (full open and full closed). That is, for 0° to 90° operation set
at minus 3° and plus 93°. Power terminals 1 and 3 for CCW rotation, terminals 1 and 4 for CW rotation (reference
paragraph 4.7.6.).
3.2 Mounting Potentiometer
3.2.1 Mounting Single Potentiometer Into Series 75 Actuator
See Figure 2.
A. With the potentiometer mounted to the potentiometer bracket and the spur gear loosely fitted to the potentiometer shaft,
mount the potentiometer bracket (if not already mounted) as follows:
10-23 75 Actuator:
Remove the motor module mounting screws on the side of the module furthest away from the actuator shaft. Position
potentiometer assembly bracket holes over screw holes and line up potentiometer shaft with center of actuator shaft,
replace and tighten screws.
25/3075 Actuator:
Attach potentiometer bracket to motor support plate between the terminal strip and actuator shaft with mounting screws
as shown.
3.2.2 Mounting Dual Potentiometer Into Series 75 Electric Actuator
A dual potentiometer is also available and is required with the AF-17 when external resistance indication is also desired, or
when the 4-20 Position Output option is also used.
Each potentiometer can serve only one function. Remote resistance monitoring and an AF-17, for instance, cannot share a
potentiometer.
Note: Voltage limit of “B” potentiometer is 30 volts maximum.
Mount potentiometer per paragraph A of 3.2.1.
3.2.3 Potentiometer Wiring
A. The feedback potentiometer leads are connected to the terminal block (TB-1) on the AF-17 board. Run the three leads up
through the hole next to potentiometer R29. See Figure 1.
B. Connect the potentiometer leads to the terminal block as follows:
NOTE 1: In the case of a dual potentiometer, “A” (front, close to the bracket) potentiometer wires are wired to the AF-17
board terminal block (TB-1) as stated above, “B” (rear, far from the bracket) potentiometer wires may be wired to terminals 7
(green), 8 (white/black), and 9 (purple) if available and the potentiometer will be used for resistive feedback, or they may be
wired to TB-2 if 4-20 mA position output option is used. The wires are run up through the hole next to Q4 then connected to
TB-2 as follows:
TB-1
Terminal Wire Color
1 Purple
2White/Black
3Green
(DO NOT CUT POTENTIOMETER WIRES!)
Flow Control Division
Worcester Controls
WCAIM2031 AF-17 Electronic Positioner: Installation, Operation and Maintenance 9
3.2.4 Adjusting Potentiometer
A. Reference paragraph 4.7.6 for moving the actuator shaft electrically.
B. 10-30 75 Actuator:
Place the large face gear (12) over the actuator shaft with the gear teeth down and secure with snap ring (16).
NOTE: The face gear utilizes a friction fit to the shaft. For best results, wipe off any lubricant that may be on the shaft
before sliding on the face gear.
CAUTION: Do not overstretch the snap ring — use the minimum opening to allow them to slip over the gear.
C. Adjust the potentiometer spur gear until there is approximately 1/
16
" engagement with the large face gear. Ensure there is
minimum backlash between the gears. Tighten the spur gear set screw.
D. Rotate the face gear back and forth to ensure smooth and easy operation of the potentiometer.
E. IMPOR
TANT: For 90° Valves:
Depending on whether the AF-17 board is installed and wired, either measure the resistance directly at the potentiometer
wires if not installed or at the AF-17 terminal block (TB-1) if installed and wired. With the actuator either in the OPEN (full
CCW) or CLOSED (full CW) position, and power off, rotate the face gear, thus turning the potentiometer shaft, until the
resistance between the white/black lead (AF-17 terminal 2) and the green lead (AF-17 terminal 3) or the white/black lead
(AF-17 terminal 2) and the purple lead (AF-17 terminal 1) respectively, as measured by ohmmeter, is between 80 ohms
and 90 ohms.
NOTE: It is not necessary to loosen or remove face gear snap ring(s) to rotate gear.
F. Power the actuator to the opposite position from where resistance was measured. Reference paragraph 4.7.6 for moving
actuator shaft electrically.
G. At this position, with power off, measure the resistance at the same terminals as stated above. The resistance reading
should be greater than 700 ohms. If not, then power actuator back to original position and adjust potentiometer again, if
necessary, as stated in paragraph E above. If unsuccessful in getting proper resistance readings, potentiometer is
defective and should be replaced.
H. The feedback potentiometer is now adjusted for use in the 75 actuator. Add the potentiometer caution label to the outside
of the actuator cover.
CAUTION: If the actuator shaft is manually rotated a multiple of 360° from its original position, the feedback
potentiometer will no longer be in calibration. It must be recalibrated per paragraphs E-G above, in order for the
AF-17 board to operate properly.
3.2.5 Important Note
The feedback potentiometer is calibrated for only one 90-degree quadrant of valve operation.
If the valve and actuator output shaft is repositioned to another 90-degree quadrant the feedback potentiometer must be
recalibrated as per Section 3.2.4.
The Series 75 actuators offer a manual override feature. Whenever repositioning the valve using the manual override
capability on these actuators, move the valve only within the 90 degrees for which the feedback potentiometer has
been calibrated.
TB-2
Terminal Wire Color
1Green
2White/Black
3 Purple
(DO NOT CUT POTENTIOMETER WIRES!)
Flow Control Division
Worcester Controls
Loading...