Operating the Converter 4-11
590 Series DC Digital Converter
Performance Adjustment
Current Loop - The Autotune Feature
Now perform an Autotune to identify and store the following Current Loop parameters:
PROP. GAIN
INT. GAIN
DISCONTINUOUS
Initial Conditions
1. Main contactor open, i.e. no Start/Run signal at terminal C3.
2. Set the AUTOTUNE parameter to OFF.
3. Program Stop (terminal B8) and Coast Stop (terminal B9) should be high, i.e. 24V.
4. If the field is being supplied by a third-party controller, remove the field manually. (If the
field is internally regulated, Autotune automatically quenches the field).
IMPORTANT: The shaft may require clamping for certain motors to prevent rotation >20% during the
Autotune sequence. If the motor is either a compound motor (series field), has some
residual magnetism, or is a permanent magnet motor it WILL rotate and the shaft must
be clamped. If in any doubt, CLAMP OR BE READY TO STOP THE MOTOR."
Performing an Autotune
• Set the AUTOTUNE parameter to ON.
• Close the main contactor, i.e. Start/Run signal to terminal C3.
• Energise the Enable terminal (C5).
The Autotune sequence is initiated. When complete (after approximately 10 seconds), the main
contactor is opened automatically signalling the end of the sequence and the AUTOTUNE
parameter is reset to OFF.
• Perform a PARAMETER SAVE now. Refer to Chapter 5: “The Man-Machine Interface
(MMI) - Saving Your Application.
• If necessary, restore field connections and remove the mechanical clamp.
Autotune Failed?
• The MMI displays the message AUTOTUNE ABORTED
If any one of the Initial Conditions above are removed, or the Autotune sequence times out
(after 2 minutes), then the Autotune sequence is aborted causing the main contactor to drop
out.
• The MMI displays the message AUTOTUNE ERROR
If during the Autotune sequence the motor speed feedback is greater than 20% of rated
speed, or the field current is detected above 6% of rated field current, then the Autotune
sequence is suspended causing the main contactor to drop out.
Note: Refer to Chapter 9: “Control Loops” - Current Control for manual tuning instructions.
Speed Loop
You will need to adjust the Speed Loop for your particular application although in most cases
the default settings are acceptable.
The optimum Speed Loop performance is achieved by adjusting the PROP. GAIN and INT.
TIME CONST. parameters.
Produce a small step-change to the speed setpoint and observe the response on the
tachogenerator feedback. If the Converter is using Microtach/Encoder feedback, then the speed
response can be monitored on Terminal A7.
Adjust the two parameters until you have rapid change of speed feedback between the setpoint
values, but with minimum overshoot.
MMI Menu Map
1
SETUP PARAMETERS
2
CURRENT LOOP
AUTOTUNE
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