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For additional assistance, please contact Toshiba Adjustable Speed Drive Marketing Dept. at (800) 872-
2192
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Make sure switch 1 (located on control board, immediately right of the phone jack) is in the up
or “I” position.
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In this example the Override Change Multiplier determines the maximum range of trim in
terms of percentage of reference. This maximum range of trim includes both positive and
negative trim bandwidths. Any amount of trim up to this maximum is available by changing
the trim terminal’s input. Maximum negative trim is achieved with minimum input on the trim
terminal’s input. Maximum positive trim is achieved with maximum input on the trim
terminal’s input.
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In this example, with the Override Change Multiplier set to “10%”, and a 4-20mA reference
into the “IV” terminal is commanding 40 hertz. When the “RR” input is 0 volts (minimum
potentiometer setting), the drive outputs 36 hertz (40 – (40 x 0.10)). When the “RR” input is
10 volts (maximum potentiometer setting), the drive outputs 44 hertz (40 + (40 x 0.10)).
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Greater trim bandwidth can be achieved by increasing the Override Change Multiplier.
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Instead of connecting a speed pot to the RR input for continuous speed trim, a user could
connect a switch with fixed resistances to give discrete levels of trim.
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Another method that requires no external connection requires setting the Override Multiplier
Input Selection to a “0”. Then the setting of the Override Change Multiplier will be added to
the frequency commanded to the “IV” terminals. For example, if the “IV” terminal is being
commanded to run 30 hertz and the Override Change Multiplier is set to “+10%”, the output
frequency will be 33 hertz, or always 10% higher than the reference signal into “IV”. An
Override Multiplier of “-10%” will always run the output frequency 10% lower than the
reference signal into “IV”.
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To verify correct operation, input 4-20 mA signal to give 60 Hz prior to setting “RX Reference
Point #1 Frequency”. As soon as this parameter is set to a non-zero value, its reference value
is added to the 4-20 mA’s reference value.
