Basics of PLC timer- PLC timers are instructions that provide the same functions as on-delay and off-delay mechanical and electronic timing relays. A PLC timer provides a preset delay to the control actions. In general, there are three types of PLC timer delays, ON-delay timer, OFF-delay timer and retentive timer on. The terms represented in the timer block in the PLC are a Preset value which means the delay period of the timer, an Accumulated value which is the current delay of the timer. A timer begins the counting on time-based intervals and continues until the accumulated value equals the preset value. When the accumulated value equals the preset time the output will be energized. Then the timer sets the output. Example of timer – The process of making tea every day in the morning for seven days (water in the tank is enough for 7 days only) Inputs: I1.1: start input I0.0: Float switch (FS) I0.1: thermostat (TH) Outputs: Q0.0: Valve Q0.2: Element Q0.4: valve Q0.1: Alarm Bell Procedure: When pressing the ‘start’ button, the valve 1 (V1) opens,so the water pass through the valve to the heating tank. And when the water level reaches the float switch (FS), the valve should close and heating must begin. When the temperature reach the required level the thermostat disconnects the heater and opens valve 2 (V2) for 10 seconds then the alarm bell is activated (as a sign that the tea jug is filled now with hot water) Follow Us On : Google Reviews : https://goo.gl/LxpEsU Facebook : https://www.facebook.com/wscubetech.india Twitter : https://twitter.com/wscube Linkedin : https://www.linkedin.com/company/wscube-tech Google + : https://plus.google.com/+wscubetechjodhpur Youtube : https://www.youtube.com/c/wscubetechjodhpur Website : http://wscubetech.com
