Important notice for Ormerod 2 and Huxley Duo owners using PanelDue

I have received a report of the 5V linear regulator of the Ormerod 2 failing some time after a PanelDue was installed. While the failure may be unconnected with the installation of a PanelDue, it may be that the linear regulator of the Ormerod 2 cannot handle the additional load of a TFT screen without additional heatsinking. I do not have an Ormerod 2 to check this on. Therefore, I have added the following to the PanelDue fitting instructions:

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The touch panel displays draw significant current from the +5V rail. The on-board switching regulator on the Duet can easily handle this. However, the linear regulator on the separate 5V regulator board used on the Ormerod 2 and Huxley Duo may not handle the additional load without additional heatsinking. Therefore, the first thing you should do [after installing PanelDue] is to monitor the temperature of the 5V regulator (the big chip on the 5V regulator board, with a black body, a metal tab at one end and 3 legs at the other end). If it is too hot to touch, then you should fit a heatsink to the regulator, screwed to the metal tab. Important: make sure that the heatsink and fitting screw cannot short against the enclosure, or anything else!

So if you are using PanelDue on an Ormerod 2, please check the temperature of the 5V regulator. I would be grateful if you could report back on this thread or by PM.

The on-board switching regulator used on the Ormerod 1 is rated at 2A, so it should have no problem with the additional load of PanelDue + touch panel.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Would a fan work also?

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Fpex
Would a fan work also?

A fan increases the rate of heat transfer to the environment, so a fan is a good way of increasing the efficiency of a heatsink. From the pictures on the RepRapPro site, it looks to me that there is no heatsink as such on the regulator board, but there has been an attempt to use the PCB to carry some of the heat away from the regulator. I can't tell whether there is efficient heat transfer between the regulator and the PCB or not - for example, whether the back of the regulator is in direct contact with the copper of the PCB. If there is efficient heat transfer between the regulator and the PCB, then a fan would indeed help.

I should point out that I do not yet know whether the 5V linear regulator on the Ormerod 2 does run uncomfortably hot with a PanelDue connected, or not. In the event that it does, another possibility would be to remove the +5V (red) wire between the Duet and PanelDue, and power PanelDue via the USB port from a cheap 5V USB power supply rated at 0.5A or more. The signal wires between PanelDue and Duet are protected by series resistors, so the order in which the Duet and PanelDue are powered up does not matter.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42

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Fpex
Would a fan work also?

A fan increases the rate of heat transfer to the environment, so a fan is a good way of increasing the efficiency of a heatsink. From the pictures on the RepRapPro site, it looks to me that there is no heatsink as such on the regulator board, but there has been an attempt to use the PCB to carry some of the heat away from the regulator. I can't tell whether there is efficient heat transfer between the regulator and the PCB or not - for example, whether the back of the regulator is in direct contact with the copper of the PCB. If there is efficient heat transfer between the regulator and the PCB, then a fan would indeed help.

From the Huxley build instructions:
"Secure the Duet and the 5V regulator PCB with six M3 nuts on the back of the enclosure-base. Make sure they are securely tightened. The one that goes through the MOSFET of the 5V regulator is particularly important; it is used to heatsink this to the enclosure back. Make sure it is securely fixed."

Wouldn't it make sense then to provide external power to the PanelDue? I am using an external PC power supply with a Duet and Duet4 Expansion. I want to add the PanelDue now and was thinking to power it off the 5V rail of the power supply. This would remove the added load from the Duet completely and allow me to switch on the both systems with one power switch.

Thoughts?

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coogrrr
Wouldn't it make sense then to provide external power to the PanelDue? I am using an external PC power supply with a Duet and Duet4 Expansion. I want to add the PanelDue now and was thinking to power it off the 5V rail of the power supply. This would remove the added load from the Duet completely and allow me to switch on the both systems with one power switch.

Thoughts?

I updated the fitting instructions a while ago. My advice now is:

1. If you have an Ormerod 1, you will either be using the on-board 5V switching regulator, or feeding 5V from your ATX PSU to the Duet. In either case, you can power the PanelDue from the expansion connector on the Duet.

2. If you have an Ormerod 2, Huxley or Mendel with the separate 5V linear regulator board, or you have a Duet 0.8 board (which is not in production yet AFAIK), then you should remove the red (+5V) wire in the cable between the PanelDue and the Duet, and power the PanelDue from a 5V USB power supply via the USB connector instead.

You could equally well use the red wire to power the PanelDue from the 5V rail of your ATX power supply, as you suggest.

HTH - David

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].