TLDR - It is normal to have your SPI outputs labeled starting with 33-48 as this makes future upgrades easier for customers.
Our Flex controller system is a modular system that allows for up to 48 outputs using either SPI and/or Long Range Regular expansion boards (Long Range Smart can have more outputs). This system has two major types of expansion boards when used with pixels:
* Long Range Expansion Board (#951-31)
* SPI Expansion Board (#951-21 or #951-22)
When the controller is built and incorporates an SPI output board with directly connected output cables, these cables need to be labeled so that a customer can determine which specific cable matches up to which output on the expansion board. As each SPI expansion board has 16 outputs, this means that with three SPI boards in a single system, the outputs would be labeled:
* 1 to 16
* 17 to 32
* 33 to 48
The issue becomes when a controller is ordered with say, only 16 SPI outputs. In that case we need to decide what number grouping we should use for the cables. Prior to the year 2022, most controllers were produced with outputs starting at the top. For example:
Board 1: Long Range Expansion (outputs 1 to 16)
Board 2: 16 SPI (outputs 17 to 32)
Board 3: Not Used
In the example above, we would have the physical cables labeled 17 to 32 since the long range expansion board took up outputs/ports 1 to 16. This was perfectly fine if the customer never upgraded and added additional boards. So, if we use the example above and add in a second Long Range Expansion Board to their existing system we get the following:
Board 1: Long Range Expansion - NEW (outputs 1 to 16)
Board 2: Long Range Expansion - EXISTING (outputs 17 to 32)
Board 3: 16 SPI - EXISTING (outputs 33 to 48) - labels stay 17 to 32
Since we must always physically put the Long Range Expansion boards at the top (above SPI boards) and due to the method that the ribbon cables are laid down, this means that the 16 SPI board must move to the third position which changed the logical outputs to 33-48 but the cables are still labeled 17-32. This then required the customer to remove all the SPI cables and relabel them to the new 33-48. Of course we don't want customer to have to rebuild all the labels on the cables when all they want to do is add an expansion board.
Additionally, internally, it was hard for us to pre-build controllers in the off-season because we didn't know how many of each count of expansion boards would be used, so we ended up with pre-assembled controllers with say 1 to 16 when we needed 17 to 32. To add to this, starting in the year 2022, we discontinued the smaller CG-1500 enclosure which was typically only used with two expansion boards and moved exclusively to the HC-2500 (for 2 Power Supply Controllers) which always allows up to three expansion boards so that customers would have easier expansion options without having to purchase a new controller box and mounting hardware.
To resolve all these issues, we moved from a 'top down' to a 'bottom up' numbering system in early 2022. This move solved all future problems with upgrades for customers as we build all SPI based controllers starting at outputs 33 to 48 - so adding a second 16 SPI board does not require any re-labeling of cables. While customers that receive a controller with only 16 SPI outputs might find this confusing since they assume it should start with 1 to 16, you'll find that within the controller itself, the outputs are labeled logically by groups. This will also make future upgrades to the flex system inexpensive and quick. This method also means that when customers are adding expansion boards to their system, they will not need to "move around" universe and mappings inside the controller, only add the new ones "on top" of the existing outputs.