Sequential Timer | Sequential Led Controller | Sequence Timer control

Sequential Timer control is important for effective cleaning of Dust Collection Systems/Filter Bags. This timer is also known as sequencer or sequential led controller that helps energize and de-energize the multiple outputs at a time. Customers can utilize the sequential timers, which plays an important role in proper De-dusting in dust collectors. Appropriate De-dusting is very important task in any dust collection systems that guarantees long life of filters and ultimately results in high production rate.

Dust collector equipments must have high filtering efficiency even for the finest dust. The proper use of time-controlled cleaning can result in less human resources. Hence high efficiency dust collector parts play a very important role here. By any measure, an efficient dust collector system is an investment that more than pays for itself.

Today we will be learning some of the Sequential led controllers, which include:

1) Solid State Sequential Timer

2) Micro Controller Sequential Led Controller

3) Continuous cleaning Sequence Timer control

4) On Demand Cleaning Sequence Timer control

1) Solid State Sequential Timer:

Sequential Timer is the major part of Dust Collector system for continuous cleaning of the system. The  pilot operated pulse valves used on dust collector system can be operated using Sequential Timer Control. Light emitting diodes (LEDs) are used to provide visual indication through which pilot valve is being charged as well as it gives “Power On” indication on the display. The series of sequenced steps is customizable  from 2 through 10.To adjust the length of time between valves being de-energized (Off time /  Pulse Frequency) and the length of time that the valve is energized ( On time / Pulse Duration) controls are provided. All logic functions and timings are controlled by Silicon semiconductor components.

Sequential Timer

To Start and stop the Controller Two independent strategies are provided. They are as follows:

1) The first strategy will consequently stop the sequence and reset the Controller to the initial valve position whenever A. C. power is detached and then again reconnected.

2) The second strategy is by a remote control contact associated with the terminals provided. At the point when the remote contact is opened, the execution stops. When the remote contact is released, the execution proceeds from the previous.

 1) Solid State Sequential Timer Operation:

The Sequential Controller gives continuous sequential energization of associated loads. The “Power On” light emitting diode (LED) gives visual indication and the Pulse Valve number 1 is immediately charged, when power is applied to the sequential led controller. LED provides visual indication of this event as “Output 1”.

For the particular length of time which is indicated by the setting of the “On time/ Pulse Duration” control, the pilot valve will remain energized. Note that the aligned dials are for estimated settings only and they must be measured, if exact times are required.

Pulse valve number 2 will consequently be charged at some time span after pilot valve number 1 has been discharged. This time span will be as shown by the setting of the “Pulse Frequency / off time” control. “Output 2” LED will give appropriate visual indication that this function is occurring. The Controller will continue to sequentially energize the pilot valves until the power is detached.

2) Micro Controller Based Sequential Led Controller:

The Dust Collector Controllers of various sequences can be programmed to suit customer’s actual necessities which are micro controller based units. This requirement can be fulfilled by using Sequential Timers.

Sequential Timer

The two basic modes of operation are: a) Program Mode b) Manual Mode

  1. a) Program mode: The unit can be programmed to follow desired set of instructions as specified by client. This mode acts as automated dust collector systems
  2. b) Manual Mode: We can process output (Pilot Valves) serially. This controller has been intended to operate the pulse solenoid valves used on dust collector systems.

The controller has been given with SEEPROM to hold programmed values of various criterions in case when there is power failure. The current data gets automatically stored in SEEPROM. This SEEPROM will store up to 1million read/write functions and the stored/existing data will be saved up to many years.

  • Operation of Micro Controller Based Sequential Led Controller:

The Micro Controller Based Bag Filter Timer provides timed sequential energization of connected loads. The Pilot valve will remain energized for the length of time as indicated by the setting of the “ON “control, when power is applied to the controller.

When we keep MENU key pressed on keyboard for approx 3sec, we can select “PROGRAM MODE” for modification in data of various specifications.

3) Continuous cleaning Sequence Timer control:

Sequential timer boards are used for continuous cleaning. This means that the timer board is continuously pulsing to purify the filters while the system is in working condition. Only limited applications require this type of sequential timers; and most of all do not. In this type of system, there is no notification status to the sequential timer control from a pressure device which continuously observes the filter status. Rather than this, the system only uses a sequential timers, like the DCT500A Series timer board, which makes use of the on-board potentiometers to set the on and off time intervals for the continuous pulsing.

Regardless of the reason why the system was developed that way, continuous cleaning could actually result in more damage than good. By continuously cleaning the filters, system could result in cleaning the filters even before they have had a chance to develop a dust matter, which is the main task for filtering purposes and protecting the filters. This can cause damage to the filters, which would end up in an added maintenance cost. In addition to this, during continuous cleaning, you are continuously using the precious compressed air, which is very costly. Therefore, in order to cope up with these issues and to optimize efficiency, manufacturers have implemented next version i.e. on-demand cleaning for mostly all applications.

 4) On Demand Cleaning Sequence Timer control:

In on-demand cleaning system, the sequential timer control does not start pulsing to clean the filter, until they seems to be dirty. This method not only helps to increase the filter efficiency and their life span, but also limits the amount of pulsing that helps to save the compressed air.

The common method for on-demand cleaning systems is to utilize a sequential timer board, such as DCT500A Series, in combination with an A3000 Series Photohelic®. The Photohelic® gage is used to monitor the filters for dust build-up. At the point when the dust build-up and pressure drop over the filters exceeds a preset limit, the Photohelic® gage activates the DCT500A’s cleaning cycle. The DCT500A then runs the cleaning process until the dust levels and corresponding pressure drop on the filters fall below the preset limit. This configuration achieves the on-demand functionality; nonetheless, it requires you to provide an enclosure for both the Photohelic and the timer board, assuming that we are referencing an outdoor application. That can make the setup and installation potentially difficult.

To help reduce your costs further and still provide you with the benefits of an on-demand cleaning system, this sequential timer is developed as all-in-one package. DCT1000 Series dust collection sequential timer controller has all the functionality of the DCT500 sequential timer control, with the added advantage of an optional plug-in for pressure module, which replaces the Photohelic® gage. This helps the customer to run differential pressure lines from across the filters right into the timer board. This not only combines all the parts into one board, but also provides a digital readout versus the dial. With the pressure module, you will also have a linear 4-20mA output which can be used to remotely monitor the pressure, if desired. Furthermore, the digital display is used in setting parameters such as on and off times versus potentiometers like the other boards.

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