Loading...
INSTALLATION
OPERATION MAINTENANCE INSTRUCTION
BULLETIN No. 418
PULSA SERIES GUARANTEE
Should you experience a problem with your Pulsafeeder pump, first consult the troubleshooting guide in your operation and maintenance manual. If the problem is not covered or cannot be solved, please contact your local Pulsafeeder Sales Representative, or our Technical Services Department for further assistance.
Trained technicians are available to diagnose your problem and arrange a solution. Solutions may include purchase of replacement parts or returning the unit to the factory for inspection and repair. All returns require a Return Authorization number to be issued by Pulsafeeder. Parts purchased to correct a warranty issue may be credited after an examination of original parts by Pulsafeeder.
Warranty parts returned as defective which test good will be sent back freight collect. No credit will be issued on any replacement electronic parts.
Any modifications or out-of-warranty repairs will be subject to bench fees and costs associated with replacement parts.
In addition, Pulsafeeder guarantees its PULSA Series drive assemblies for a period of two years from the date of shipment. All other material and workmanship are fully covered for a period of one year. Any parts found to be defective within the above time span will be replaced free of charge, F.O.B. factory.
Equipment or accessories manufactured by others but purchased through Pulsafeeder, such as electric motors, are guaranteed only to the extent of the original manufacturer.
Damages incurred from misuse, abuse, and/or improper protection during storage will be cause to void the guarantee. Erosion, corrosion, or improper application of the equipment or related piping by the buyer or any third party is also excluded from the guarantee.
The above guarantee is in lieu of any other guarantee, either expressed or implied. We make no warranty of fitness or merchantability. No agent of ours is authorized to make any warranty other than the above.
Safety Considerations:
1.Read and understand all related instructions and documentation before attempting to install or maintain this equipment
2.Observe all special instructions, notes, and cautions.
3.Act with care and exercise good common sense and judgment during all installation, adjustment, and maintenance procedures.
4.Ensure that all safety and work procedures and standards that are applicable to your company and facility are followed during the installation, maintenance, and operation of this equipment.
Information in this document is subject to change without notice. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or any means electronic or mechanical, including photocopying and recording for any purpose other than the purchaser’s personal use without the written permission of Pulsafeeder, Inc.
ii
|
|
Table of Contents |
|
1. INTRODUCTION ........................................................................................................................................ |
1 |
||
|
1.1 |
General Description ................................................................................................................ |
1 |
|
1.2 |
Options ..................................................................................................................................... |
3 |
|
1.3 |
Input Signals ............................................................................................................................ |
3 |
|
1.4 |
Control Modes ......................................................................................................................... |
4 |
|
1.5 |
Current Output Signals........................................................................................................... |
4 |
2. |
EQUIPMENT INSPECTION ....................................................................................................................... |
5 |
|
3. |
PROCEDURAL NOTES............................................................................................................................ |
5 |
|
4. |
INSTALLATION ...................................................................................................................................... |
6 |
|
|
4.1 |
Wiring Up.................................................................................................................................. |
6 |
|
4.2 |
Start Up..................................................................................................................................... |
6 |
5. |
CALIBRATION ....................................................................................................................................... |
7 |
|
|
5.1 |
Deadband Adjustment ............................................................................................................ |
7 |
|
5.2 |
Circuit Board Calibration........................................................................................................ |
7 |
|
5.3 |
Meter Readout (current Output) Calibration......................................................................... |
9 |
|
5.4 |
Auto-Manual Calibration......................................................................................................... |
10 |
6. |
REPAIRS ........................................................................................................................................... |
11 |
|
|
6.1 |
Limit Switch Adjustment......................................................................................................... |
11 |
|
6.2 |
Potentiometer .......................................................................................................................... |
11 |
|
6.3 |
Zero Alignment ........................................................................................................................ |
12 |
|
6.4 |
Brake Air Gap........................................................................................................................... |
13 |
|
6.5 |
Jammed Slider Block .............................................................................................................. |
14 |
7. |
ORDERING PARTS................................................................................................................................. |
15 |
|
8. |
CONVERSION (MANUAL TO PULSAMATIC) .............................................................................................. |
15 |
|
9. |
TROUBLESHOOTING CHART................................................................................................................... |
16 |
|
Conventions
For the remainder of this bulletin, the following Conventions are in effect.
A WARNING DEFINES A CONDITION THAT COULD CAUSE DAMAGE TO BOTH THE EQUIPMENT AND THE PERSONNEL OPERATING IT. PAY CLOSE ATTENTION TO ANY WARNING.
Notes are general information meant to make operating the equipment easier.
Tips have been included within this bulletin to help the operator run the equipment in the most efficient manner possible. These “Tips” are drawn from the knowledge and experience of our staff engineers, and input from the field.
iii
1. Introduction
1.1General Description
The PULSAmatic actuator converts reciprocating motion of the pump into rotary motion to turn the pump’s stroke adjustment screw. By selectively engaging either of the two oppositely oriented, one-way clutches, one of two corresponding nuts hat ordinarily rotate freely on a “diamond” actuator shaft is blocked form rotation when the shaft moves longitudinally in one direction. Thus locked, the nut compels the shaft to rotate, thereby turning the adjustment screw to which it is connected.
The actuator assembly consists of the following major components: the actuator shaft (a major portion of which is in the form of a diamond screw), tow brake housings, two one-way clutches, and two helix nuts. Mounted side-by-side, the two brake housings are concentric to the axis of the actuator shaft. The helix nuts are located between the inner walls of the brake housings and the surface of the shaft. One nut engages the right-hand thread of the shaft and other engages the lefthand thread. Each nut rotates within a one-way clutch.
In operation, the actuator shaft reciprocates along its axis. When the brakes are de-energized, each nut, along with its respective clutch, is free to rotate in alternation clockwise and counterclockwise directions as it is driven by grooves in the shaft. Under this condition, the shaft and adjustment screw do not rotate.
Upon energizing one of the brakes, the corresponding one-way clutch is utilized allowing the nut to rotate only in one direction, while the shaft is moving longitudinally during the e discharge stroke of the pump (linear motion of the shaft is now in the opposite direction), the clutch prevents the nut from rotating, causing the shaft to rotate. This rotation is transmitted by a mechanism inside the gearbox housing to the pump adjustment screw so that the piston stroke length is changed. By energizing the other brake, the adjustment screw is rotated in the opposite direction. To increase or decrease pump output, it is only necessary to selectively energize either brake.
Rotary motion of the actuator shaft also rotates a sleeve which in turn drives a gear train through a spur gear pressed on one end of the sleeve. The gear train transfers outputs for a positional feedback potentiometer and limit switches. A bevel gear mounted on the opposite side of the drive sleeve is meshed with a hand wheel bevel gear and mechanical stroke position indicator.
A printed circuit board contains standard and optional control circuits. The incoming command signal is compared with the internal feedback signal. If the two are equal or nearly so, no action occurs. If the command signal is greater, one brake is energized, resulting in a corresponding change in pump output (stroke length) and feedback signal. If the feedback signal is greater than the command signal, the other brake is energized, changing the pump output and feedback signal in the reverse direction. When the feedback signal matches the command signal, stroke length is properly positioned and adjustment is halted.
The override switch, operable from outside the actuator assembly, disconnects the brakes from the circuit board to permit manual adjustment using the hand wheel. The “out” position is for manual operation and the “in” position is for automatic operation.
2
1.2Options
The PULSAmatic actuator is configured at the factory for a variety of options, both singly and in various combinations. The appropriate wiring diagrams external to the circuit board are included with each pump shipment.
1.3Input Signals
.
Standard signals are:
1-5 mA DC @ 2000 ohm Impedance
4-20 mA DC @ 470 ohm Impedance
10-50 mA DC @ 180 ohm Impedance
0-10 V DC @ Greater than 270,000 ohm Impedance
Slide wire (Remote, 1000-ohm manual control potentiometer, user-supplied).
Actions
Direct Acting- minimum and maximum input signal levels correspond directly to minimum and maximum stroke settings respectively. For example, a 4-20 mA signal ranges stroke from zero at 4mA to full at 20 mA. This is the standard mode of action.
Reverse Acting- Signal response is inverted relative to direct acting. For example, a 4-20 mA signal ranges stroke from full at 4 mA to zero at 20 mA. This is an optional mode of action.
3
1.4Control Modes
Ratio Control- When ratio control is applied, the range of stroke adjustment is proportionally reduced to a level equal to the ratio setting. For example, at a ratio setting of 60%, the full span of the input signal commands the pump to operate between zero and 60% of full stroke rather than over the full range of the stroke. The ratio is manually set between zero and 100% using a remote potentiometer.
Split Ranging- A single control signal command s two pumps, each pump responding only to a portion of the total range of the signal. The PULSAmatic controller operates specifically as follows: One pump is commanded from zero to full stroke over the lower half of the input signal, and a second pump is commanded, in the reverse-acting mode, from full to zero stroke over the higher half of the input signal. For example, a 4-20 mA input signal controls the first pump between zero stroke at 4mA to full stroke at 12 mA and controls the second pump between full stroke at 12 mA and zero stroke at 20 mA
Manual- Remote manual stroke adjustment potentiometer.
Auto-Manual- Remote switch selection between automatic and remote manual operation.
1.5Current Output Signals
0-10 mA DC – 500 ohm Impedance max. 4-20 mA DC – 250 ohm Impedance max.
4
2.Equipment Inspection
1.Check all equipment for completeness against the order and for shipping damage. Shortages or damage should be reported immediately to your PULSA Series representative.
2.Check pump and PULSAmatic stroke control identification tags for serial and model numbers. There are two tags: one on the pump gearbox which includes the pump model number and another on the PULSAmatic enclosure. The pump gearbox serial number identifies the PULSAmatic actuator as well as any separately mounted control stations. Each should correspond to the information on the parts lists. Use these reference numbers whenever corresponding with the factory.
3.Check the envelope containing this bulletin for service parts list and special drawings and wiring diagrams for specified control options.
3.Procedural Notes
Electrical repairs and calibrations should be undertaken only by an electronic technician q2ualified in the maintenance and repair of linear (analog) industrial process control equipment.
A digital voltmeter and a process control signal generator are required for electronic calibrations.
Troubleshooting and repair may require access to the mechanism linking the actuator control to the oscillating housing inside the pump gearbox. This requires removal and replacement of the rear gearbox cover assembly. Refer to the pump operations manual for the description of these operations.
Detailed circuit board schematics, containing component identifications, are available from the factory to facilitate electronic circuit troubleshooting and repair at the board level.
The following conventions and procedures apply throughout this bulletin.
1.“Zero Stroke” refers to a zero, or (000) setting on the mechanical stroke counter. “Full Stroke” refers to a full or (100) setting on the mechanical stroke counter.
2.A “low end” input control signal is one that commands the pump to zero stroke A “high end” input control signal is one that commands the pump to full stroke.
Note that the signal values are inverted in the reverse acting option so that, for example, a 4-20 mA signal commands full to zero stroke. In this case, 4 mA is the high end signal. See “Options” under “principals of Operation” above for signal definitions.
3.Pump stroke can be manually or automatically set as required for calibrations and adjustments. References to the disable switch (“out” for manual, “in” for automatic) may be omitted. Manual, or hand wheel adjustments made while the pump is not operating, require that pressures be relieved from both the suction and discharge lines.
4.Wiring terminals are indentified on the circuit board and referred to directly. For example TB2-3 refers to terminal No. 3 on Terminal Board No. 2, (reference Figure 4).
CAUTION: When troubleshooting, always remove signal potential prior to disconnecting AC power. This will help protect integrated circuits on the circuit board.
5
4. INSTALLATION
4.1Wiring Up
(Refer to any special wiring diagrams and installation drawings supplied by Pulsafeeder).
AC power lines should be routed to the actuator via a separate conduit from the control signal and any optional accessory wiring. A separate switched and protected circuit is recommended for the actuator power supply.
Remove the PULSAmatic actuator cover, which is secured by two screws, or screwed on, in the case of an explosion proof enclosure. The two power transformers should be wired as described by wiring diagrams. Power and ground wire should be No. 18 AWG wire size or larger. A power ground screw is provided on the backing plate near the conduit openings. Terminal TB1-4 is also provided as an optional circuit board ground. This terminal is connected to the circuit board ground through a 4700 ohm resistor.
Run the signal and accessory wiring using the alternative conduit opening. No. 22 AWG wire size or larger is recommended. Make all connections per the diagram that apply to the combination of signal and accessories provided.
Explosion proof actuators are Underwriters Laboratories (UL) listed and are labeled with the hazardous environments for which they are rated, along with any special installation specifications required in support of UL listing. They must be installed, wired, operated, and maintained in accordance with local electrical codes.
CAUTION: To help protect the integrated circuits in the servo amplifier, always energize AC power prior to connecting the signal leads.
4.2Start Up
Ever actuator is adjusted and calibrated at the factory. However, due to variations in input signals RECALIBRATION IS REQUIRED. Prior to performing this procedure (as outlined in the next section) it is recommended that the following steps be followed in order to verify proper mechanical operation and limit switch adjustment.
Mechanical Operation- Before applying electrical power, remove the coupling guard between pump and motor and manually rotate the motor shaft through several revolutions. The thin metal brake armatures should rotate in alternate directions as the actuator shaft moves first in one direction and then the other. (If they do not, the actuator linkage may be disconnected from the oscillating housing under the main cover). Replace the motor coupling guard.
Limit Switch Verification- with the counter indicating 090 or less, pull out the handwheel and rotate to increase the count. As a value of 200 is approached (from 099 to 100) a faint click should be heard from one of the limit switches. If an audible indication of the limit switch operation cannot be obtained, operation may be verified electrically. Turn the handwheel back to a counter indication of 090 and pull out the override switch. Continuity should exist between the terminals of the limit switch mounted on a double switch bracket, farthest from the printed circuit board. Pull out and slowly rotate the handwheel so that the counter indication increases. The switch should open, indicated by loss of continuity, when the stroke indicator reads between 097 and 100.
6
Operation of the second limit switch (the one closest to the circuit board) may be checked in a similar manner. The limit switch should be open at a stroke indicator reading between 001 and 000.
If either of the limit switches appears to be out of adjustment refer to “repairsLimit Switch Adjustment”.
Barring any problems proceed with “Calibrations and Adjustments”.
Refer also to the “Equipment Startup” section of the pump Installation, Operation, and Maintenance Instructions.
5. Calibration
As stated previously, field recalibration is required upon startup. The following procures are to be performed in sequence as presented. Refer to Figure 4 as required for circuit component locations.
5.1Deadband Adjustment
With pump stroke positioned exactly as commanded by the input signal, a certain change in signal must occur in either direction (increase or decrease) in order to cause the actuator to respond.
For example, if a pump is operating at 50% stroke in response to a 50% input signal, the signal must typically increase to 51% or decrease to 49% before the actuator does not respond, or is “dead”, is called “deadband”. If deadband is too narrow, the actuator will frequently make slight adjustments in response o small signal variations. In the extreme case, the actuator will continually “hunt” back and forth over a small range of adjustment. If deadband is too broad, response will lag and accuracy will suffer. The “Null” potentiometer near the center of the circuit board adjusts deadband. Clockwise movement decreases deadband, increasing sensitivity. Counterclockwise movement increases deadband, decreasing sensitivity.
Deadband adjustment for response to a 1% change in signal (depicted in the example above) is appropriate to most installations. This can be set approximately by setting the “Null” potentiometer in the six o’clock position shown in Figure 4. To check deadband adjustment, cycle the pump automatically, by input signal command, to an approximately midrange stroke setting. Leaving the override switch in the “in” or automatic position, slowly adjust the handwheel in either direction until the actuator responds to return the stroke to the original set point. Care must be taken during this operation, as the handwheel will move without warning. Deadband is observed on the mechanical stroke indicator as the difference between the original stroke setting and that at which the actuator responds.
5.2Circuit Board Calibration
The PULSAmatic circuit senses all control signals in terms of voltage. A current signal is converted to a voltage signal measured across a resistor, provided in the circuit board, through which the current passes. For example, the most commons signal, 4-20 mA DC, passes through a 470 ohm resistor to generate a 1.88-9.40 volt DC signal, (0-6.3 v with Ratio Control).
This procedure trims the actuator circuits to the low and high ends of the actual input control signal.
7
Without Ratio Control – Coarse Adjustment
1.Place the override switch in the “out” or manual position. The pump need not be running for coarse adjustment.
2.Set up a voltmeter to read a full scale DC voltage of 10.
3.Connect the positive lead of the voltmeter to TB2-2 and the negative lead to TB2-1.
4.Set the control signal at the low end (0%) and record the voltage.
5.Set the control signal at the high end (100%) and record the voltage.
6.Set up a voltmeter for DC voltage measurement between TB2-5 (positive) and TB2-1 (common).
7.Adjust the “LO” trim potentiometer on the circuit board to the voltage recorded in step 4.
8.Set up the voltmeter for DC voltage measurement between TB2-4 (positive) and TB201 (common).
9.Adjust the “HI” trim potentiometer on the circuit board to the voltage recorded in step 5.
10.The above adjustments are interactive. It may be necessary to repeat steps (2) through (5) several times until the voltages stabilize. This completes coarse adjustment.
Without Ratio Control – Fine Adjustment
11.With the override switch still in the “out” or manual position start the pump.
12.Set up a voltmeter for DC voltage measurement between TB2-3 (positive) and TB2-1 (common).
13.Set the control signal at the low end (0%). Move the override switch to the “in” or auto position. The LO” drive LED will light and the pump with automatically adjust to the 0% stroke.
14.Adjust the “LO” trim potentiometer on the circuit board to the voltage recorded in step (4). The stroke indicator should now read 000-001 and both LED drive lights should be off.
15.Apply a high end (100%) control signal. Allow the pump to adjust to 100% stroke.
16.With the voltmeter remaining as set up in step (12) above, adjust the “HI” trim potentiometer to the voltage recorded in step (5). The stroke indicator should now read 099-100 and again both drive lights should be off.
17.The above adjustments are interactive. It may be necessary to repeat steps (12) through (16) several times until the voltages stabilize. This completes fine adjustment.
With Ratio Control (Optional Feature) – Coarse Adjustment
1.With the override switch in the “out” or manual position, start the pump.
2.Set the controls signal at the low end (0%). Move the override switch “in” to the auto position and allow the pump to adjust to 0%.
3.Place the override switch back in the “out” or manual position. Check the stroke indicator; if it does not read 000-001 use the handwheel to manually adjust it to this point.
4.Set the remote ratio control potentiometer at 100%.
5.Set up the voltmeter for DC voltage measurement between TB3-4 (positive) and TB3-6 (common).
8
Loading...