While David's post explains the mechanics for making the change, note that a 1-minute timestep may not be a very useful output:

1. output: 1. Many occupancy schedules are not entered at that high a resolution (schedules are generally hourly).
2. hourly). 2. The weather file has hourly data, so it will not reflect, e.g., rapid changes in cloud coverage (solar radiation) or windspeed.
3. windspeed. 3. EnergyPlus does not model actual bang-bang thermostat control for HVAC systems; rather, if the HVAC is ever needed to meet the load for a timestep, a simple part load ratio is calculated. (Newer versions of EnergyPlus may now have this capability, I'm not sure.)