Chromalox MaxPac, Руководство пользователя, Страница: 27 / 44

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1. Set Current Limit (I LIM) pot to 0% for full current output (CCW).
Current Limit is for limiting current for loads that have
extreme hot to cold resistance ratios or are overrated. We
recommend for these types of loads to adjust I LIM (Cur-
rent Limit) to 50% or less. This will also decrease voltage as
well as current. 0% Current Limit gives 100% current output
(CCW). 100% Current Limit gives 10% current output (CW).
2. Set Manual (MAN) pot to zero so unit will not be biased above
input (CCW).
Manual control adjustment provides a means of setting the
output level of the MaxPac Power Pak in the absence of
controlling instrumentation. The manual control signal value
“adds” to the controlling instrument to set minimum output.
The desired output power level may be set by adjusting the
manual control. This value of output will then be present even
in the absence of a control signal.
3. Set Remote Manual pot to zero output so unit will not be biased
above input (CCW). (Jumper pins 4 & 5 if not used.)
Remote Manual control adjustment provides a means of
setting the output level of the MaxPac Power Pak in the
absence of controlling instrumentation. The Remote Manual
control is also effective when a control signal is connected.
The Remote Manual control signal value “adds” to the
controlling instrument to set minimum output. The desired
output power level may be set by adjusting the Remote
Manual control. This value of output will then be present even
in the absence of a control signal. Connect Remote Manual
pot wire to Pin 4 (CCW), Pin 5 (W), and Pin 6 (CW) of plug-in
connector.
4. Check for open contact for Emergency Stop.
Emergency Stop inhibits all SCR trigger pulses regardless
of the level of the input signal or manual potentiometer. For
Emergency Stop, close contact Pin 7 to Pin 8 of plug-in con-
nector. Leave contacts open for operation.
5. Check for polarity of input signal.
6. Adjust input signal to low end of scale.
Zero Adjust control sets the power output starting point or
reference. Thus, it effectively cancels positive inputs to the
MaxPac Power Pak.
EXAMPLE: 0 - 5 mA input à set to 0 mA input
4 - 20 mA input à set to 4 mA input
7. With power off, connect line voltage and load as shown.
8. Connect meter to input and output.
WARNING: Set meter to correct scale to read proper
input or output.
9. Apply power to unit.
10. Adjust input signal to low end of scale.
11. Using the Zero pot, adjust the output voltage just to zero volts.
12. Adjust input signal to top end of scale.
Gain Adjust Control sets the maximum power output for
maximum input signal.
EXAMPLE: 0 - 5 mA input: set to 5 mA input
4 - 20 mA input: set to 20 mA input
13. Using the Gain pot, adjust output voltage just to maximum
volts.
14. Repeat steps 11, 12, 13, and 14 until no adjustment is
necessary of Zero and Gain pots for proper output voltage
indication. Voltage output should increase proportionally to the
signal input applied.
15. Adjust input signal to low end of scale (zero voltage output).
16. With Manual pot at zero for zero voltage output, adjust (CW)
to 100% for full voltage output. Voltage output should
increase proportionally. Return to CCW position and output will
decrease to zero output.
17. With Remote Manual at zero for zero voltage output, adjust
(CW) to 100% for full voltage output. Voltage output should
increase proportionally. Return to CCW position and output will
decrease to zero output.
18. With Manual pot (CW) at 100% and I LIM (Current Limit)
at 0%, adjust I LIM towards 100% noting that voltage output
decreases with the adjustment of the Current Limit pot. Adjust
Current Limit pot for your application, if needed.
19. Turn POWER OFF and remove meters. TEST COMPLETE.
4.2.6 - Calibration (MaxPac IP):
Many high-temperature heating elements exhibit extreme hot to cold resistance ratios. Heating elements composed of Platinum,
Molybdenum, Tungsten, and Tantalum, to name a few, draw excessive current on start-up. Depending on the mass of the elements,
these “high starting currents” may exist for extended periods of time. Generally, once the elements have achieved their normal operat-
ing temperatures, the current drawn through the MaxPac Power Pak will fall within the rating of the unit. For these types of loads, we
recommend adjusting the I LIM (Current Limit) to 50% or less. This will decrease voltage as well as current.