The alarm module replicates the alarm block of the function module. It works like an alarm clock. In the case of a rising edge at the trigger input, an internal counter is set to the value that is present at the time input. At the same time, the counter starts to count backwards. When the counter has reached zero, Output 1 is set for a second to 1 (afterwards the zero is sent). If the cycle input is set to 1 after the time expires, the counter is started again. A cyclical output is thus created, whereby the cycle time always depends on the time input. The meter reading is frozen when the freeze input is 1. If the input is reset, the counter continues with the last value. If a second rising edge is at the trigger input before the counter is 0, the counter is set back to the value at the time input (retriggerable). If the trigger input is initialised at the start of value 1, this is interpreted as a rising edge after HS/FS is restarted and the alarm module started. The module is only started when the value at the time input > 0. The alarm module also has a further output that sends the remaining time in seconds after each second at the bus.