Can the Power Modulator be accessed/controlled by a home automation system?
The SCPM can indeed get an optional input from either another snow sensor or Smart home indication using the C, R, 1 terminals.
The built-in controller in the cabinet has a parameter in the technical settings that define what zones (heating outputs) will be activated by the SCPM-SS-120 (snow sensor) and which zones will be activated by the extra internal connection C/R/1.
If one wishes to have both a snow sensor and the Smart-home input work together (whatever signal is positive- the system will be activated), then one will need to order the new model of the built-in power modulator controller that was released late in 2017 (we do not yet have this version as of 1/1/18). In the new version, the P[07] “P07 - Heaters outputs logic controlled by SCPM-SS-120 snow melt sensor or by WarmlyYours sensor” has an additional option to activate the system with both sensors.
In order to control the unit externally, feed terminal 1 with 24VAC as the input signal.
It was designed to allow a regular thermostat (24VAC operated. we supply the 24VAC from the “C” & “R”) to activate the heaters in the gutter (or similar) based on other input than the Snow-sensor. One will need to provide a 24VAC signal to the “1” terminal.