The controller can be connected to an optional bypass module (please see Bypass). With the bypass the system can be operated in either On-Line mode (load is supplied by inverters) or in Off-Line mode (load is supplied by mains). The configuration is to be set in the controller module. Some additional configuration values can be altered when a bypass is connected:

Voltage limits: When a load is fed by a mains supply that has permanent distortions, the voltage limits can be changed to more suitable values, percentagewise, in order to avoid repeatingly switching. The limits for undervoltage can be altered to -10/-15/-25%, the overvoltage limits can be set to +10/+15%.

It is recommended to alter the values only with relatively insensitive loads attached, electrical machines or heaters, respectively. For sensitive loads like computers or measuring equipment, running the system in On-Line mode would be the more suitable option, since the output voltage of the inverters is generated and stabilized by processors. This only applies when having a distorted mains sine, though.