====== 2.6 Stacking of IOL HAT Pro ======

Two IOL HAT Pro can be stacked on top of each other:

{{:iol-hat:hw-pro:2_connections:2-6_stack.png?400&direct}}

To ensure proper operation, set JP1 to Port 1+2 on one IOL HAT Pro and JP1 to port 3+4 on the other IOL HAT Pro. If you decide to control the IOL enable through the Raspberry Pi (GPIO23, Jumper JP2), the enable signal applies for both IOL HAT Pro.

===== Raspberry Pi power supply considerations =====

<WRAP Important>

If you are powering the Raspberry Pi through the IOL HAT, please ensure that only one of the IOL HAT Pro has JP3 set.

</WRAP>

===== 24 V distribution =====
If you power the IOL HAT Pro through X5 (round connector), you can use X6 to connect 24V between the boards:

{{:iol-hat:hw-pro:2_connections:2-6-1_connect-x5.png?300&direct}}

If you connect via X6, you need to connect both boards over the X6 connection:
{{:iol-hat:hw-pro:2_connections:2-6-2_connect-x6.png?300&direct}}