Controllers for optically switchable devices

A window controller system for controlling multiple optically switchable devices, the window controller system comprising:

• an enclosure, wherein the enclosure comprises a 3-gang or a 4-gang outlet box and a faceplate;
• and
• a first printed circuit board comprising a plurality of components, the plurality of components comprising:
• a plurality of insulated glass unit (IGU) controllers, each configured to control an IGU of a corresponding plurality of IGUs operatively coupled to the window controller system;
• and a processing unit configured to control each of the plurality of IGU controllers and to characterize leakage current from one or more IGUs of the corresponding plurality of IGUs;
• wherein a first IGU controller of the IGU controllers is configured to respond to a leakage current from a first IGU of the IGUs during a hold state by applying a holding voltage periodically to the first IGU, thereby bringing an electrochromic device to a predetermined optical state.

A method for controlling tinting of multiple optically switchable devices, the method comprising:

• (a) applying, via a window controller, a drive voltage to two or more optically switchable devices in connection with a tint transition from a first tint state to a second tint state, wherein applying the drive voltage to the two or more optically switchable devices comprises providing a voltage from a power supply common to the two or more optically switchable devices;
• (b) monitoring, for each of the two or more optically switchable devices, parameters indicative of a state of the tint transition;
• (c) repeating (a) and (b) until it is determined that one or more optically switchable devices have completed the tint transition to the second tint state;
• (d) in response to determining at (c) that the one or more optically switchable devices have completed the tint transition to the second tint state, applying hold voltages to the one or more optically switchable devices while concurrently continuing to apply the drive voltage to a remaining one or more optically switchable devices of the two or more optically switchable devices that have not completed the tint transition;
• (e) repeating (b)-(d) until the two or more optically switchable devices have completed the tint transition;
• (f) characterizing leakage current from one or more of the optically switchable devices;
• and
• (g) responding to a leakage current from an optically switchable device during a hold state by applying a holding voltage periodically to the optically switchable device, thereby bringing the optically switchable device to a predetermined optical state.