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Electronic Theatre Controls Inc

How many stations does a Paradigm Processor and Station Power Module support

Question

What is the correct quantity of LON-based stations a Paradigm Architectural Control Processor (P-ACP), Paradigm Station Power Module / Mk2 (P-SPM / P-SPM-E), and Paradigm Repeater Module (P-REP / P-DREP) will support? I've heard/seen conflicting answers.

Answer

The amounts for each product are listed below:

Product Station Count
P-ACP 63
P-SPM-E 63
P-SPM 31
P-REP/P-DREP 31

ETC's implementation of the LON bus supports a total of 64 devices, and since a P-ACP counts as a device, and is the start of the LON bus, that leaves a maximum of 63 stations that can be connected to the LON bus. The P-SPM-E supports the full 63 station compliment by itself, due to . A P-REP or P-DREP can be added to increase wire length, but would not increase your station count because the bus already supports the maximum about of stations. The original P-SPM only supported 31 stations, so adding a P-REP increased both wire length and station count.

If you're doing the math you'll notice the the P-SPM and P-REP only equal 62, one short of the P-ACP's maximum. This is because the P-REP is the start of a second LON bus, and must include itself against the overall count against the P-ACP, thus leaving its supported count at 31, instead of 32.