Discussion on the logical control principle of dual backup devices
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Gentlemen, I have a question for your help: In the design of some mechanical devices, it may be necessary to have multiple backup units, such as 1 in use with 2 backups, 2 in use with 2 backups, 3 in use with 2 backups, or 5 in use with 3 backups, and so on. For example: in a pump system with two in use and two as backups, four pumps are installed on site, with pumps A and B operating while pumps C and D remain idling. Now, pump A suddenly breaks down. So, how can we logically determine whether it is Pump C that operates automatically or Pump D? What is the basis for operation?
This post was last edited by t*ngtou on 2017-2-13 08:35. Our control method here is as follows: 1. So, how can we logically determine whether it should be Pump C that operates automatically or Pump D? On the pump’s on-site control panel, each pump is equipped with a selection switch corresponding to the three operating modes of LEAD\STANBY\LOG. Pumps that are in the LEAD state continue to operate. When one pump is not sufficient, the pump in the STANBY state comes online; if two pumps are still not enough, then the pump in the LOG state comes online. 2. What is the basis for operation? Here, operation is based on the pressure at the pump outlet; four pressure values are taken into account in the program. The first three values are used to control the start of the pumps, while the last value is used to stop them. Pumps in LOG mode are stopped first, followed by those in STANBY mode. For the original poster’s reference
If any one of the pumps fails, it is possible to start a pump from among A\B\C\D... by beginning anew. Before starting a new pump, restrictions must be set; for example, if the number of already running pumps exceeds a certain value, no further pumps can be started. In essence, it’s still a sequential startup process, only pumps that do not meet the conditions are not started