Electronics AC-24 User Manual

Instruction Manual

MagnaV alve Amperage Controller

Electronics Inc.

56790 Magnetic Drive

Mishawaka, Indiana 46545

1-800-832-5653 (Toll Free)

Phone: [phone]
Fax: [phone]
E-mail: [e-mail]
Website: www.electronics-inc.com

Model AC-24 Control

IM:0078 Revision: D Date: 1/11/2008

Made in the USA

Table of Contents

PRODUCT DESCRIPTION 3

THEORY OF OPERATION 3

LOCATION OF ADJUSTMENTS 3

PRELIMINARY ADJUSTMENTS 3

OPERATION 4

STABILITY ADJUSTMENT 6

MOTOR AMPS FULL SCALE DISPLAY 6

MOTOR AMPS CALIBRATION 7

WARRANTY 7

UPGRADES — REVISIONS 7

TROUBLE-SHOOTING GUIDE 7

EXAMPLES 9

CALCULATING FLOW RATE (Pounds per minute) 10

SPECIFICATIONS 11

WIRING CONNECTIONS 11

FIGURE 1: FRONT PANEL (Operator Controls) 12

FIGURE 2: FRONT PANEL (Technical Adjustments) 13

TABLES FOR CALCULATING FLOW IN POUNDS/MINUTE 14

TROUBLESHOOTING ASSISTANCE FORM 15

HOW TO RETURN CONTROLLERS FOR REPAIR 16

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1. PRODUCT DESCRIPTION

The Model AC-24 Amperage Controller is used with wheel-type shot peening and blast clean­ing machines to measure and control the rate of flow of steel shot passing through a special
normally-closed magnetic valve called a MagnaValve. A digital display is provided for indica­tions of motor amps. A 0-10 Volt dc output signal proportional to motor amps is available for
remote indication or strip-chart recorder. High and low alarms are set to bracket the re­quested amperage setting. The alarm bandwidth is adjustable from the front panel. Either lo­cal (front panel) or remote 0-10 Vdc setpoint commands may be used.

Caution: The motor amps current transformer wiring to the 50 mOhm current
shunt at terminals #5 and #7 must be less than 10 feet (3 M) of 16AWG wire,
otherwise the digital display reading will show lower than actual amps.

Terminal #6 can be used for signal input for motors with variable- speed
drives that have a 0-5Vdc output for current or load monitor. See section 14
for additional wiring information.

2. THEORY OF OPERATION

The desired motor amps setpoint is compared with the actual motor amperage and a servo
command signal is sent to the MagnaValve to permit shot to flow and to achieve desired mo­tor amps. If the desired amperage is not achieved within an adjustable time period, then a
high/low alarm relay will be triggered. The MagnaValve uses permanent magnets to hold the
shot and electro-magnets to cancel the magnetic field. When power is applied to electro­magnets the shot is free to flow.

3. LOCATION OF ADJUSTMENTS

For location of adjustments see Figures 1 and 2. Numbers in parenthesis (figure-balloon) rep­resent figure number and balloon call-out number. For example, digital display is (1-3), mean­ing figure 1 and balloon number 3. Notice that the yellow buttons also require you to use the
▼ or ▲ buttons to change the display readings. The black buttons act alone to change the
status of a function.

4. PRELIMINARY ADJUSTMENTS

A. Apply 24Vdc power to AC controller.
B. If the 24Vdc power is less than 23Vdc or greater than 26Vdc then the all of the front panel

LEDs will flash.
C. The digital display (1-1) should read 0.0 when the motor is off.
D. Verify that the Controller full-scale range matches the current transformer (or the range of

the motor speed control if using the 10Vdc input option). Push and hold the display range

button (2-21) to show the full-scale range. Typical factory setting is 100.0 amps for full

scale display. To change this value continue to hold (2-28 or 29) while you push (1-12) to

increase or (1-11) to decrease the full-scale range.
E. For automatic machine cycle, push the mode button (2-20) until the ready mode led (1-6)

is on.
F. When an “Enable” signal is received, the “ON” LED indicator (1-7) on the front panel will

light and activate the valve output. The red bar graph LED (2-13) will display the magni-

tude of the servo command signal sent to the MagnaValve.
G. Adjust the motor amps setpoint (1-8) and ▼ or ▲ to desired motor amperage level.
H. Select the alarm band mode, either percentage of setpoint (PT) or percentage of full-scale

(FS) by pushing (2-16)

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I. To set the alarm bandwidth push (1-4) and ▼ or ▲. The alarm bandwidth is relative to this

value and is centered at the setpoint command. Typical setting is 5% of Full Scale (FS).

J. Adjust the alarm delay time by pushing (2-17) and ▼ or ▲. Typically setting is 5 seconds.

5. OPERATION

Operation consists of controlling motor amps by modulating the shot flow rate through the
MagnaValve and transmitting an alarm signal when motor amps is above or below the desired
amperage. The servo circuit controls the output voltage signal for the MagnaValve by compar­ing the setpoint command with the actual motor amps.

A. SETPOINT

1. Setpoint may be adjusted at any time, either with or without the enable signal.

2. To set desired motor amps in the local setpoint mode be sure the indicator (1-9) is on.
If it is not on then push (2-27). Next, push the setpoint button(1-8) and the ▼ or ▲ but­tons. The setpoint value will be shown in the digital display (1-1).

3. To set desire motor amps in the remote setpoint mode push (2-19) until the indicator (1

-10) is on.

B. ENABLE MODE: The enable mode button (2-22) controls the operating modes that are

displayed by indicators “Off” (1-5), “Ready” (1-6) and “On” (1-7). Push the Mode button (2

-22 to go through the sequences of Off-Ready-On as shown by the LEDs.

1. Enable mode “Off”: In this mode the MagnaValve will stay turned off, even if an enable
signal is received.

2. Enable mode “On”: In this mode the MagnaValve will be turned on whether or not the
enable signal is present.

3. Enable mode “Ready”: In this mode the MagnaValve will only be turned on if the en-

able signal is received.

C. ENABLE DELAY:

The Enable Delay (2-30) is factory set to zero. This feature is used only when a time delay
is required after the receipt of the enable signal before the MagnaValve is activated. This
feature is typically not used in wheel blast applications of the MagnaValve. To change the
setting push Enable Delay (2-30) and ▼ or▲

D. ALARM:

High and low alarm conditions are shown by LEDs (1-3) and (1-2).

1. The alarm bandwidth may be calculated relative to either full scale (FS) or setpoint
(SP) as shown by indicators (2-15) and (2-14).

2. To change from one alarm band mode to the other push (2-16).

3. The alarm bandwidth is adjustable from 0 to 50% of full-scale and is factory set at 5%.
Customer may readjust to another value as desired.

4. The midpoint of the alarm band automatically follows the setpoint setting.

5. To increase or decrease the alarm band push button (2-16) and ▼ or ▲.

6. The alarm circuit is only activated when the servo is “on” and the control is enabled.
When the control is enabled, the “Enable On” LED (1-4), on the front panel will be on.

7. The alarm relay contacts will activate after a short time delay (see next section for
alarm delay).

8. The alarm function can be inhibited by applying an alarm reset signal (24Vdc) to termi­nal 12.

9. The alarm band, usually set at 5% of full scale, will track the motor amps setpoint set-

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ting. For example: for an alarm band of 5 Amps and a setpoint of 30 Amps will have
alarms set at 25 and 35 amps. Moving the setpoint to 45 Amps will cause the alarms to
move to 40 and 50 Amps.

E. ALARM DELAY:

An adjustable time delay of 1-10 seconds is set by the alarm delay button (2-17) and the ▼
or ▲ buttons. The delay timer will start each time the “high” or “low” light comes on. If the
fault lasts longer than the timer setting, the high (or low) light will get brighter and the high
(or low) alarm relay contact will transfer and latch. The alarm will stay on after the “Enable”
signal is removed until the alarm is reset by application of the 24Vdc alarm reset signal or
the next reception of the enable signal.

F. ALARM RESET:

1. Application of the 24Vdc alarm reset signal at terminal 12 will cancel the alarm relay
and the alarm “high” or “low” LED’s will go off. Continuous application of the reset sig­nal will disable or inhibit the alarm output signal.

2. The alarms are automatically reset upon receipt of each new “Enable” command and
therefore using the manual alarm reset function may not be necessary.

G. REMOTE MODE

1. A remote setpoint command may be used in place of the front panel setting. The set­point LED (1-5) must be on. This is controlled by setpoint button (2-27)

2. Apply a 0 - 10 Vdc analog remote setpoint command signal to the remote input terminal

2. A 0 Volt dc signal will correspond to a 0% motor amps command; and 10 Vdc signal
will correspond to a 100% display range. To verify the setpoint command, push and
hold the setpoint switch. The remote command may come from a remote pot or any 0 ­10 Vdc signal source. An internal reference 10 Vdc excitation voltage for a remote po­tentiometer (10K OHM) is available at terminal 2.

H. RECORDER OUTPUT

1. A recorder output analog voltage signal proportional to motor Amps is available at ter­minal 18. It has a range of 0 - 10 Vdc and is provided to operate a strip-chart recorder
or analog input card in data loggers. The minimum load on this output is 10K Ohms.
Shielded cable should be used and the shield should be connected to the AC control­ler’s chassis ground. Additional electrical noise filtering may be necessary at the input
terminals of your analog input card to prevent erroneous readings.

I. MAGNAVALVE OUTPUT SIGNAL

1. The MagnaValve uses permanent magnets and electromagnet solenoids to control the
flow of steel shot or grit, therefore it has no moving parts. During operation of the Mag­naValve a red LED bar graph display (2-13) shows the relative magnitude of the servo
command signal sent to the MagnaValve.

2. The MagnaValve also has a LED to show this function. This LED will pulse at approxi­mately an 8-15 Hertz rate with the duty cycle (on-time to off-time ratio) proportional to
shot flow rate and motor amps. A low-duty cycle will provide low shot flow rate and low
motor amps and the Valve LED will be relatively dim. A long, or continuously on, duty
cycle will provide for a high shot-flow rate and high motor amps. At 100% duty cycle the
Valve LED is constantly on, the permanent magnet field is completely canceled, and no
magnetic field exists in the MagnaValve therefore allowing shot to fall freely through the
valve.

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