The 18R Controller does not support cycling through multiple modules. If multiple modules are on the same channel, the 18R will report module continuity as it comes in intermittently.
The 18R2 Controller does, however, support continuity checks across multiple modules by repeatedly pressing the TEST button to cycle through each module while displaying the address at the same time. If you would like to see if you qualify for the 18R to 18R2 trade-in credit program please email help@cobrafiringsystems.com for eligibility.