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Troubleshooting
Possible causes:
- Mechanical slippage in the motor gearing - fix the mechanical issue
- Low battery volts, causing the Arduino to crash or reboot
- Poor electrical connection in the wiring
We have had several users report that the shutter "stops half way" when opening or closing. Generally, this turns out to be because the battery is deficient, or because there is a wiring fault.
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Check your battery volts with a multi-meter while disconnected from the charger. The voltages shoule be within the following ranges. Note that discharging a battery below the minimum allowed voltage normally causes permanent damage or degradation.
- LiFePO4 4S/12V battery - Minimum 10V, nominal 12V - 12.8V, fully charged 14.6V
- Sealed Lead-Acid (SLA) 6S/12V - Minimum 10.5V, nominal 12.6V, fully charged 13.2V - 14.0V (varies, check data sheet)
- Other - see Wikipedia: Comparison of Battery Types
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Tighten screws on terminal blocks, sometimes these work loose with vibration.
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Check condition of all cables and replace if necessary
In firmware version 4.0.0 we introduced an "auto-close on low battery" feature which may help to prevent over-discharge. When using this feature, the low voltage threshold should allow a generous margin above the minimum. The auto-close should happen while the battery still has enough charge to close the shutter. You will have to determine this by trial and error. The feature is disabled by default and needs to be enabled by configuring a minimum voltage threshold.
Possible causes:
- Close position sensor installed incorrectly (see Shutter Open and Closed Sensor Positioning).
- Mechanical slippage in the shutter mechanism causes the firmware to lose track of its position
In the case of mechanical slippage, the first course of action should be to address the mechanical issue. Reliable firmware operation depends on correct and smooth mechanical operation as a prerequisite, and no amount of changing settings or adding fixes to the firmware is going to change that. It is not possible to create a "software victory over hardware".
Once you have resolved the mechanical issue, then the firmware can be resynchronized by manually moving it to the fully closed position using the toggle switch. When the closed sensor is detected, the firmware will re-sync its zero position automatically.
If you are using the dome remotely and need to close the shutter in an emergency, if you can log in and get terminal access, then you can force-update the firmware's current position. If you write a large step position and then issue the close command, the shutter will close either until it reaches the sensor or the zero step position. Proceed as follows:
- Use a terminal emulator such as PuTTY to connect to the rotator's serial port. Make sure you have closed down any software that might be holding the serial port open.
- Issue the command
@FRRto check your connection. You should see the firmware version string reported. - Determine the shutter's current position by issuing the command
@PRS(position read shutter). You can use this value to assess whether the shutter's position appears to be accurate. - Determine the shutter's maximum step position by issuing
@RRS(Range Read Shutter). Make a note of the returned maximum position. - Force teh shutter's current position to be the maximum, with
@PWS,12345(Position Write Shutter - replace12345with the maximum step position obtained in the previous step). - Issue the close command:
@CLS. The shutter should close all the way.
Refer to the documentation for a full list of firmware commands.
Don't forget to fix the mechanical issue as soon as possible, or the problem will recur.
You may have an incorrect setting for the maximum shutter travel. This may be due to corrupted EEPROM (settings).
This condition has been observed when V3 firmware has been used, then downgraded to V2 firmware, then up to V3 again. V3 firmware attempts to validate the settings by writing a 'fingerprint' but in the scenario described, this appears to not always work, leaving the settings corrupted and causing erratic operation.
We suggest resetting to factory defaults.
This is usually a sign of incorrect or corrupted settings.
This condition has been observed when V3 firmware has been used, then downgraded to V2 firmware, then up to V3 again. V3 firmware attempts to validate the settings by writing a 'fingerprint' but in the scenario described, this appears to not always work, leaving the settings corrupted and causing erratic operation.
We suggest resetting to factory defaults.
EEPROM (settings) may be corrupted.
You should be able to use a single operation of the toggle switch to perform at least one full dome rotation, or fully open/close the shutter. If this is not the case, then the likely cause is that there are incorrect settings for dome circumference or shutter limit of travel.
This can happen if the settings have been incorrectly configured, or if the EEPROM memory has somehow become corrupted.
An example of this condition can be seen on the Facebook page of a NexDome user.
This condition has been observed when V3 firmware has been used, then downgraded to V2 firmware, then up to V3 again. V3 firmware attempts to validate the settings by writing a 'fingerprint' but in the scenario described, this appears to not always work, leaving the settings corrupted and causing erratic operation.
We suggest resetting to factory defaults.
This condition is known as a motor stall and is generally a mechanical or electrical issue. Although the sound can be very unpleasant, stalling is not usually harmful to the motor but the condition does need to be investigated and resolved or the dome may not operate correctly.
Stalling can occur when the motor cannot produce enough torque to overcome mechanical forces acting against it. Possible causes are:
- The motor has insufficient current or voltage
- The motor is being driven too fast or accelerating too quickly
- Mechanical issues such as exessive friction or binding or moving parts
- The stepper drive module is configured incorrectly.
Sometimes, stalling can be mitigated by changing motor maximum speeds and acceleration curves.
The default settings are suitable for a typical dome that has been installed correctly. You can adjust the motor speeds and acceleration curves to compensate for some adverse conditions, or if you are controlling a third party structure that requires different settings.
If you need to decrease motor speed or increase acceleration ramp time, then that is potentially a sign of mechanical issues and you should check your installation to make sure there are no unnecessary or excessive forces hindering operation of the moving parts.
- Check that power supply volts (rotator) and battery volts (shutter) are with specifications.
- The shutter should be tested with the battery at full charge: about 14 volts. The battery is fully discharged at 11 volts and operation below that threshold is known to cause stalling issues.
- The rotator power supply should maintain 12 volts when the motor is running and particularly during the first few moments as the motor begins to accelerate. If the supply voltage dips significantly during motor start-up, then the power supply may be faulty or inadequate.
- Check that DIP switches on the stepper driver module are set according to factory defaults.
- Try increasing the acceleration ramp time (Setup dialog)
- Try decreasing the motor maximum speed (setup dialog)
This can occur due to variations in how the motors are wired. There are many ways to wire stepper motors and none of them are harmful to the electronics. if the motor wires are not corrected to the correct terminals on the stepper motor drive module. This has been found to be the case in some units. We have seen instancesThere can be variation in the wire colours when the stepper motors are made
Pull out the green 4-way connector where the motor wires enter the stepper drive module. The connector will come out with the wires still attached. Make sure the power is off before connecting or disconnecting any wires or connectors.
We suggest wiring from left to right: Black-Green-Red-Blue. This is the normal wiring for units delivered from the factory. If this still doesn't resolve your issue, then you should probably contact NexDome for advice.
Re-plug the connector and re-test. The dome should rotate such that azimuth increases clockwise.
Note: if there is inconsistent operation when controlled by software vs. the toggle switch, then the toggle switch wires might be reversed. You can either reverse the order of the wires at the X4 terminal block, or pop the switch out of the enclosure, rotate it 180 degrees and snap it back in.