TUNING

TM 5-3895-374-24-1 GP470FA TUNING The DC200E controller modulates the exhaust damper actuator in order to maintain dryer draft at the setpoint value. The controller output ranges from 0 to 100% and is split between the Open and Close output relays as illustrated in figure 5. Fig. 5 The length of time that the output relays remain energized is calculated by the controller based on the following information: DEVIATION: The difference (+ or -) between the setpoint value and the measured draft. PROPORTIONAL BAND: Determines the percent output that the controller will produce to correct the error. Decreasing the proportional band will result in a larger output change in response to a deviation from setpoint. The proportional band should be set as low as possible without causing the system to cycle continuously. Changes to the proportional band setting may be made by the following procedure: 1. Press [SET UP] until the display reads SET UP TUNING. 2. Press the [FUNCTION] key once. The lower display will read PB and the upper display will show the current proportional band value. (page 3-42)