Emerson Exchange 365

digital integrator with time limit.

hello every one ,im trying to do the following can any help me to solve it :-

we have new low tension motor and this motor can be started only three times per hour not more ,ie if it started and tripped or stopped  for any reason 3 times during one hour operator can not start it until one hour finished.some one advise me to do digital integrator with time limit and reset.but i dont know how to do it.  

mrc_tech

• 1 Nov 2017 3:08 PM
• Cancel

2 Replies

• Neil Castro

  

  • 1 Nov 2017 10:07 PM

  I presume you are using DC block in controlling the new motor. I also presume that you either assign a permissive or interlock on the 3 start/restart limit within an hour. There are countless ways in performing what you want. One example is using a timer and an expression block (i.e. ACT block) that signals the permissive/interlock when the motor is attempted to restart more than 3 times within an hour.
  
  Other configurations like the use of an integrator or SFC can also be used.

  • Cancel
• Matt Forbis

  

  • 3 Nov 2017 3:03 PM

  On some of my projects, we have created an external module to handle keeping track of the starts. We have 6 parameters in the module that are normally defaulted to 0. Each time the motor starts, we look for the next parameter that is still 0 and set it to a positive value. For all parameters that are non-zero, we increment them each time the module scans. Once the timer reaches the configured time period, such as an hour, we reset the value back to 0. This basically allows us to keep track of up to the last 6 times the motor started. As long as the number of values greater than 0 is less than the max starts per hour, you can start the motor. Once the number of counters is greater than the number of allowed starts per time period, then you no longer allow a start of the motor. In the motor module itself, you can use a permissive condition referencing this external module to keep the motor from starting again if there is not a start available. Finally, if you want to display how long until they can start the module, you take the max of your different counters and subtract from the time period to find when the next start would be available. Since this was paid for by a customer, I can't give you en export, but I can answer questions if you need more details.

  • Cancel