2 Functions of Devices in DVP-PLC EH2/SV/EH3/SV2 series MPU: Functions of step relays: The step relay S can easily set up the procedure in the industrial automation, which is the most basic device in the sequential function chart (SFC) and has to be used with STL, RET instructions. The device No. of S is S0 ~ S1023 (total 1,024 points) and both step relay S and output relay Y have output coils and contact A, B, and there is no limitation on the times of using the contact. S cannot directly drive the external load. When the step relay is not used in SFC, it can be used as a normal auxiliary relay. There are four types of step relays: 1. Initial step relay:
S0 ~ S9, total 10 points, used for initial steps. 2. Zero return step relay: S10 ~ S19, total 10 points. S10 ~ S19 are planned for zero return when used with API 60 IST instruction in the program. If they are not used with IST, they will become normal step relays. 3. General purpose step relay: S20 ~ S511, total 492 points (for SA/SX/SC series MPU); S20 ~ S499, total 480 when the operation of the PLC encounters power cut. points (for EH2/SV/EH3/SV2 series MPU). Used for general purposes in SFC and their status will all be cleared 4. Latched step relay:
S512 ~ S895, total 384 points (for SA/SX/SC series MPU); S20 ~ S127, total 108 points (for ES/EX/SS series MPU); S500 ~ S899, total 400 points (for EH2/SV/EH3/SV2 series MPU). Used for latched function in SFC and their status will all be retained when the operation of the PLC encounters power cut. They will remain at the status before the power cut when the PLC is powered again. 5. Alarm step relay: S896 ~ S1023, total 128 points (for SA/SX/SC series MPU); S900 ~ S1023, total 124 points (for EH2/SV/EH3/SV2 series MPU). Used with alarm driving instruction API 46 ANS as an alarm contact for recording the alarm messages or eliminating external malfunctions.
2.6 Numbering and Functions of Timers [T] No. of timers (in decimal) ES/EX/SS series MPU: SA/SX/SC series MPU: DVP-PLC Application Manual 2-15 Initial S0 ~ S9, 10 points. Can be modified to be latched by setting up parameters. Total 1,024 points Zero return S10 ~ S19, 10 points, used with IST instruction. Can be modified to be latched by setting up parameters. General purpose S20 ~ S499, 480 points. Can be modified to be latched by setting up parameters. Step relay S Latched S500 ~ S899, 400 points. Can be modified to be non-latched by setting up parameters. Alarm S900 ~ S1023, 124 points. Can be modified to be latched by setting up parameters.
100ms general purpose T0 ~ T63, 64 points Total 128 points Timer T 10ms general purpose T64 ~ T126, 63 points (M1028 = On:10ms; M1028 = Off:100ms) 1ms general purpose T127, 1 point 100ms general purpose T0 ~ T199, 200 points. T192 ~ T199 are the timers for subroutine. Fixed to be non-latched Total 256 points 100ms accumulative T250 ~ T255, 6 points. Fixed to be latched. Time T 10ms general purpose T200 ~ T239, 40 points. Fixed to be non-latched 10ms accumulative T240 ~ T245, 6 points. Fixed to be latched. 1ms accumulative T246 ~ T249, 4 points. Fixed to be latched.