C h a p t e r 5 D e v i c e5 - 1 35_5.2.5 Output Relays (Y) Output functionThe output sends the ON/OFF signal to drive the load connected to the output, such as an external signallamp, a digital display, or an electromagnetic valve. There are four types of outputs: relays, transistors (NPNand PNP), and TRIACs (thyristors). You can use the output contact A or contact B several times in theprogram. Use output Y only once in the program; otherwise, according the PLC’s program-scanningprinciple, the state of the output depends on the circuit connected to the last output Y in the program. Output number (the decimal number)For the PLC, the output numbers start from Y0.0. The number of outputs varies with the number of outputson the digital input/output modules. The outputs are numbered according to the order in which the digitalinput/output modules are connected to the PLC. The maximum number of outputs on the PLC is 1024, andthe range is between Y0.0 and Y63.15.An output that is not used as an output device can be used as a general device. Output typesOutputs are classified into two types.1. Regenerated output: The state of a regenerated output is not written until the program executes theinstruction END according to the states of the outputs. For example, OUT Y0.0.2. Direct output: The state of a direct output is written by the PLC during the execution of the instructionsaccording to the states of the outputs. For example, OUT DY0.0.5.2.6 Auxiliary Relays (M)The auxiliary relay has contact A and contact B. It can be used several times in the program. You can combinethe control loops with the auxiliary relay, but you cannot drive the external load with the auxiliary relay. You canuse the auxiliary relays in either of two ways.1. For general use: In general use, if an electrical power interruption occurs when the PLC is running,the auxiliary relay is reset to OFF. When the power is restored, the auxiliary relayremains OFF.2. For latched use: In latched use, if an electrical power interruption occurs when the PLC is running,the state of the auxiliary relay states for latched use is retained. When the powersupply is restored, the state remains the same as before the power interruption.5.2.7 Special Auxiliary Relays (SM)Every special auxiliary relay has its own specific function. Refer to section 2.2.7 in the AS Series ProgrammingManual for more information.
