Can a single TS4-M unit monitor a full string? Can a single TS4-S or TS4-F unit disconnect an entire string?

The TS4 solution functions on the module level, so the data received will be data from only the specific modules with the TS4-M covers. You may extrapolate string current from a single module, as the current in one module must be the same as the current throughout the string, however voltage and power values will only represent the individual module.

The rapid shutdown feature of TS4-S and TS4-F also functions on the module level.  For NEC 2014 Rapid Shutdown compliance, all modules in the system need TS4-S functionality or above, or TS4-F on all modules.