NF DP420LS Instruction Manual page 188

 Setting the polarity of the state output
1. Press the MENU key to move to the root menu, then select [System]. The system setting
window opens.
2. In the [ExtOut Pol] item, select [1: Negative] or [2: Positive].
DP420LS/DP480LS
4.18 Control Using External Control Function
169