Electronics AC - Manual (Page 5)

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signal source. An internal reference 10 Vdc excitation voltage for a remote potentiometer
(10K OHM) is available at Terminal #4.
h. MODE SWITCH (1-11) - The mode switch is used to turn the control “on” or “off” or enable
the remote “Ready” mode.
i. RECORDER OUTPUT- A recorder output analog voltage signal at terminal #20 with a 0 -
10 Vdc range is available to operate a strip-chart recorder or analog input card in data log-
gers. The minimum load on this output is 10K Ohms. Shielded cable should be used and
the shield should be connected to AC® controller’s chassis ground. Additional noise filter-
ing may be necessary at the input terminals of the analog input card to prevent erroneous
readings from the recorder output.
5. STABILITY ADJUSTMENTS - (SERVO STABILITY)
The servo adjustments have been factory set to typical settings but the customer may fine-tune
these settings to optimize the speed of response. Since many factors determine system stability,
these adjustments should be made slowly.
SERVO GAIN - This adjustment sets the gain of the error amplifier over a range of 1% to
100%. Most systems may operate at 50%. If the motor current is unstable, then reduce the
gain to 25%.
SERVO RESET
- This adjustment determines the speed at which the output signal increases
to achieve desired motor current. A 50% value is set at factory for typical applications. Turning
the servo reset clockwise will make it faster and turning it counter clockwise will make it
slower.
If the shot flow rate and motor current are not steady, it will be necessary to perform a simple sta-
bility test. Place the servo switch (2-11) in its off position. Enable the control and slowly increase
the setpoint from 0% until the display reads the desired operating value. If the operation at this
time is unstable, then it is the system that is unstable. Since the control is in manual mode, if mo-
tor current is unstable, then the machine itself is causing a problem, not the servo adjustments
(because the servo is off). Refer to the Trouble-Shooting Section 12.
6. MOTOR CURRENT CALIBRATION (Span)
Caution
: The factory has preset the span adjustment so that 5 A AC input will result in a full-
scale display reading. To accommodate different ranges of current transformers, such as 100:5
or 50:5, change the Display Full-Scale Adjustments, not the span setting. See section 7.
DO NOT ADJUST THE AC® CONTROLLER SPAN, IT HAS BEEN FACTORY SET AND
SEALED.
7. MOTOR CURRENT FULL SCALE DISPLAY
The standard factory setting is for 100:5 current transformers. To use other current transformer
ratios proceed as follows:
a. Apply power to AC controller.