Chapter 2 Devices 2.2.9 Stepping Relays (S) You can easily use the stepping relay in industrial automation to set a procedure. It is the most basic device in sequential function chart (SFC) programming. Refer to the ISPSoft User Manual for more information on sequential function chart programming. There are 2048 stepping relays, (S0 – S2047). Every stepping relay is like an output relay in that it has an output coil, contact A, and contact B. You can use a stepping relay several times in a program, but the relay cannot directly drive the 2_ external load. In addition, you can use the stepping relay as a general auxiliary relay when it is not used in a sequential function chart.
2.2.10 Timers (T) This topic describes the timers available in ISPSoft. Refer to the ISPSoft User Manual for more information on timers. 100 millisecond timer: The timer specified by the TMR instruction takes 100 milliseconds as the timing unit. 1 millisecond timer: The timer specified by the TMRH instruction takes 1 millisecond as the timing unit. The accumulative timers are ST0–ST511. If you want to use the device-monitoring function, these timers can monitor T0–T511. If you use the same timer repeatedly in a program, including in different TMR and TMRH instructions, the timer setting value is the one that the timer matches first.
If you use the same timer repeatedly in a program, the timer is OFF when one of the conditional contacts is OFF. If you use the same timer in a program as the timer for a subroutine’s exclusive use and an accumulative timer in the program, it is OFF when one of the conditional contacts is OFF. When the timer switches from ON to OFF and the conditional contact is ON, the timer is reset and counts again. When the TMR instruction is executed, the specified timer coil is ON and the timer begins to count. When the value of the timer matches the timer setting value (value of the timer ≧ setting value), the state of the contact is ON. A.
General-purpose timers When the TMR instruction is executed, the general-purpose timer begins to count. When the value of the timer matches the timer setting value, the output coil is ON. • When X0=ON and the timer takes 100 ms as the timing unit, the output coil T0 is ON when the value of the timer = timer setting value100. • When X0=OFF or the power is off, the value of the timer is 0 and the output coil T0 is OFF. 2-45