The DP180 is factory-calibrated for installation on a wall or other vertical surface and requires no field adjustment. If you mount the DP180 on a horizontal surface, there may be a slight zero shift that depends on the range of the sensor. Whenever possible, correct any zero or span offsets by software adjustment in the user’s control system. You can access both zero and span adjustments under the cover of the unit, below and to the right of the wiring terminal strip.