Extended Pulse &and Retentive Delay Timer (SS) ｜How to understand the Extended Pulse Timer (SE) and Retentive Delay Timer (SS)?
Do you still remember the previously discussed Pulse Timer (SP) and Delay Timer (SD)? Today, we are going to introduce two new timers: the Extended Pulse Timer (SE) and the Retentive Delay Timer (SS).
The Extended Pulse Timer (SE) is an upgraded version of the Pulse Timer (SP), and the main difference lies in the requirements for the start signal. Let's take a look at the timing diagram of the Pulse Timer (SP) introduced earlier:
When the start signal (I2.1) transitions from 0 to 1, the Pulse Timer (SP) begins timing, and the output of the timer (Q4.0) transitions from 0 to 1. If the start signal (I2.1) remains at 1, when the timing period (t) elapses, the output of the timer (Q4.0) transitions from 1 to 0. However, if the start signal (I2.1) transitions from 1 to 0 before time t elapses, the output of the timer (Q4.0) transitions from 1 to 0, and the timer stops counting.
So, what are the differences with the Extended Pulse Timer (SE)? The timing diagram for the Extended Pulse Timer (SE) is shown below:
When the start signal (I2.1) transitions from 0 to 1, the Extended Pulse Timer (SE) begins timing, and the output of the timer (Q4.0) transitions from 0 to 1, similar to the Pulse Timer (SP). If, before time t elapses, the start signal (I2.1) transitions from 1 to 0 and remains 0, the Extended Pulse Timer (SE) continues counting, and the output (Q4.0) remains at 1 until time t elapses, then the output (Q4.0) transitions from 1 to 0. If, before time t elapses, the start signal (I2.1) transitions from 1 to 0 and then back to 1, the Extended Pulse Timer (SE) restarts counting, and the output (Q4.0) remains at 1 until time t elapses again, after which the output (Q4.0) transitions from 1 to 0. The reset signal (I2.2) can stop the timer and reset the output (Q4.0) to 0.
In other words, once the Extended Pulse Timer (SE) starts, regardless of changes in the start signal, it will complete the set time (restarting if there are multiple transitions) and then reset the output. On the other hand, for the Pulse Timer (SP), the start signal needs to remain active to complete the preset time.
Similarly, the Delay Timer (SD) and Retentive Delay Timer (SS) follow similar patterns. The timing diagram for the Delay Timer (SD) is shown below:
When the start signal (I2.1) transitions from 0 to 1, the Delay Timer (SD) begins counting, and the output of the timer (Q4.0) remains at 0. When the start signal (I2.1) remains at 1, and after the set time t elapses, the output of the timer (Q4.0) transitions from 0 to 1 and stays at 1. When the start signal (I2.1) transitions from 1 to 0, the output of the timer (Q4.0) also transitions from 1 to 0.
The timing diagram for the Retentive Delay Timer (SS) is shown below:
When the start signal (I2.1) transitions from 0 to 1, the Retentive Delay Timer (SS) begins counting, and the output of the timer (Q4.0) remains at 0. When the set time t elapses, the output of the timer (Q4.0) transitions from 0 to 1. If, before reaching the set time t, the start signal (I2.1) transitions from 1 to 0 and remains 0, the timer continues counting until the preset time t is reached, and the output (Q4.0) transitions from 0 to 1. If, between reaching the set time t and the start signal (I2.1) transitioning from 1 to 0, the start signal (I2.1) transitions from 1 to 0 and then back to 1, the timer restarts counting. The reset (I2.2) signal can stop the timer and reset the output (Q4.0) to 0.
Indeed, it has a bit of complexity, doesn't it? You can revisit the previous articles for further clarification: