Connect a 10-way ribbon cable between socket X5 on the PanelDue and socket CONN_SD on the Duet 2. The connector is a standard 10 pin 2 row 2.54mm pitch box connector that accepts IDC connectors for 1.27mm ribbon cable.

(Photo from the awesome https://www.flickr.com/photos/adafruit/1...)

In tests using standard 28awg 1.27mm spaced ribbon cable, 400mm worked reliably but 800mm did not. So 400mm is the maximum recommended cable length. You can also get 26awg 1.27mm ribbon cable, and by using such cable you may be able to achieve reliable operation with cables longer than 400mm.

Caution: if you are using a thermocouple and/or PT100 daughter board, the use of long ribbon cables between the Duet and PanelDue may affect communication between the Duet and the daughter boards, because the ribbon cable connection to the SD card on PanelDue uses the same SPI bus as the daughter boards.

Use' a 4-way cable terminated in Molex KK or compatible connectors as shown here:

The length of the 4-way cable is not critical, however the resistance per conductor should not exceed 0.1 ohm. The SD card socket on the TFT panel will not be functional. The cables supplied by Escher3D and Duet3D are about 800mm long.

Use the 4-way cable as described above. If you are using PanelDue 2.0 or 3.0 with Duet 2 (WiFi/Ethernet) then you can optionally connect the ribbon cable as well in order to use the SD card socket on the TFT panel.

Use a 4-core cable terminated in a Molex KK or compatible connector at the PanelDue end and a 2x4 Dupont-style connector at the Duet end. This plugs into the end of the expansion connector. See https://miscsolutions.wordpress.com/pane....

This information also applies to a stand alone SD or micro SD card socket

You can use the external SD card socket on the LCD panel if you have used a ribbon cable as described above. Please note, the SPI interface provided by this SD card socket is much slower than the on-board SD card socket built into the Duet. Therefore we recommend that you do not upload files to this card over the network. Use the external SD card socket only if you want to write files to the SD card on a PC and then move the SD card to your printer.

To access the second SD card socket, you will need these firmware versions:

• DuetWiFiFirmware/RepRapFirmware 1.16 or later
• DuetWebControl 1.13 or later
• PanelDue firmware 1.15c or later

Caution! Do not use an SD extender cable from the SD socket on the Panel Due. Some types of SD card extender cable have been found to damage the SD card socket. Damage to the SD card socket from using an extender cable is not covered by the warranty.

You will need to make a custom 5-way cable using this table of connections. For the PanelDue 1.1, the X5 connector pins are numbered from the bottom end of the connector (the end close to the X5 legend). On the Duet 0.6 and 0.8.5 you need RepRapFirmware 1.17d or later to get support for the second SD card.