CONTREX CX-1200 - Manual (Page 305)

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STD SIGNAL TESTS
The STD Signal Tests screens allow you to test the control output and the frequency inputs. The STD
Signals Tests / Frequency Inputs screen (page 1) displays the Monitor Parameters that are associated with
FI1 Frequency Input and the FI2 Frequency Input. Input a known frequency and monitor the results here.
Use the STD Signals Tests / Control Output screen (page 2) to test the Control Output (CO_Sig). The
Control Output (CO_Sig) is the CX-1200 output signal that is input to the drive. Temporarily disconnect the
signal from the drive and use a scope or voltmeter to verify the Control Output (CO_Sig) operation.
NOTE: The CX-1200 must be in “F-Stop" when you begin the diagnostics. To start the diagnostics, enter a
“1” for Unwind, "2" for Wind or "3" for Both into Diagnostics En (CP-450) and press the Enter key.
Select the type of output test in Diag DAC Test (CP-453). The output test types are:
2 = Immediate Output (an immediate step to a constant voltage)
1 = Continuous Ramp (a continuous ramp to plus and minus voltage - if bipolar mode)
0 = Disabled (default)
In continuous ramp (1), you can set the ramp time.
Diag DAC Volts (CP-454) determines the voltage that is output for the “Immediate Output” test (2). This is
also the peak voltage that the “Continuous Ramp” test (1) will reach. Diag DAC Bits (CP-455) also
determines the voltage, but in terms of the DAC bit value. Diag DAC Test (CP-453) is limited to + CO Max
Volts (CP-271).
Diag Rmp Tm (CP-456) determines the slope of the ramp for the continuous ramp. This is the time in
seconds that it takes to increase the voltage from 0 volts to the Diag DAC Volts (CP-454). In order to get
every possible bit combination, the continuous ramp must ramp at a time of 32.767 seconds or more and the
Diag DAC Volts (CP-454) must be equal to the CO Max Volts (CP-271). In this scenario, CO Max Volts
(CP-271) must be 15 volts. The ramp should appear without discontinuity, even at low voltage.
The purpose of the CO Offset (CP-273) is to cancel any electrical offsets that may be present on the
Control Output (CO_Sig) when the CX-1200 is calling for “0” volts on the output. Set Diagnostics En (CP-
450) to “1” for (ON) and Diag DAC Test (CP-453) to “2” (Immediate Output), then set the Diag DAC Volts
(CP-454) to “0” and measure the voltage on pin J3-1 relative to J3-2. Enter the negative of the voltage
reading in CO Offset (CP-273) and then verify that the voltage on the Control Output (CO_Sig) reads at or
close to “0” volts.