Chapter 5 Basic Instructions Symbol: NED S 1 ： Specified device Bit ANED S 2 ： For internal use Bit ONED Explanation: 1. NED/ANED/ONED corresponds to LDF/ANDF/ORF. The only difference between NED/ANED/ONED and LDF/ANDF/ORF lies in the fact that users need to specify the bit device S 2 in which the previous state of the contact is stored when NED/ANED/ONED is executed. Please do not use the device S 2 repeatedly in the program. Otherwise, the wrong execution result will appear. 2. The instruction ANED is used to connect the falling-edge detection of the contact in series. 3. The instruction ONED is used to connect the falling-edge detection of the contact in parallel. 4.
Only when NED/ANED/ONED is scanned can the state of the device be gotten, and not until NED/ANED/ONED is scanned next time can whether the state of the device changes be judged. 5. NED/ANED/ONED only can be used in the function block. Example: 1. The falling -edge detection of X0.0 starts, the falling -edge detection of X0.1 is connected in series, the falling -edge detection of X0.2 is connected in parallel, and the coil Y0.0 is driven. 2. When both X0.0 and X0.1 are switched from OFF to ON, or when X0.2 is switched from OFF to ON, Y0.0 is ON for a scan cycle.
5-15 Instruction code Operand Function NED/ANED/ONED S , S 1 2 Starting the falling-edge detection/Connecting the falling-edge detection in series/Connecting the falling-edge detection in parallel Device DX DY X Y M SM S T C HC D L PR S 1 ● ● ● ● ● ● ● ● ● ● ● S 2 ● ● ● ● ● ● ● ● ● ● ●