Those who have used the Yokogawa CS3000, please come in
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For the pumps in our company, safety reasons require that startup conditions be included in the sequential control system: the MV value must be less than or equal to 5; otherwise, the pump cannot start. However, after a power outage and when power is restored, things can get complicated, and sometimes it is forgotten to set the MV value to zero. As a result, once the pump is started, it rotates at high speed, which is very dangerous. The sequential control system does not function in such cases. I have checked that the control settings are correct – for example, for pump A110, the settings specify that if the MV value is greater than 5 before startup, then DO-A110B should be OFF (although it should be ON when starting). DO-A110B corresponds to module SO-1. I’m not sure why this setting does not work. I would be very grateful if anyone with expertise could help resolve this issue! !
You mean a pump with variable frequency, right? A logic can be implemented such that when the pump stops, the MV output is forced to 0.
Read the manual more often to find the detailed instructions for using the DO-A110B with the SO-1 module
Our company used Yokogawa in the past, but has switched to other brands in recent years.
Our plant uses the Yokogawa CS3000 for air separation; it’s entirely in English, so it’s not easy to understand. You can try what was mentioned on the 2nd floor.
Thank you all for your support. I know it’s possible to force the pump MV to zero, but this is the case with all pumps that come equipped with variable frequency drives; I’m not sure why.
I believe the main reason is that the DCS does not function during startup on-site; only when the system is switched to automatic mode on-site and startup is carried out via the DCS does the sequence control table work. If it’s not the case above, then check whether the sequence control table is set to automatic mode.
Yes! ! ! If the contents in the sequence control table are useful, they can only be activated in automatic mode! ! ! ! ! ! I’ve encountered this problem! ! ! !
Thank you, I’ve checked the sequence control table – it’s always on automatic mode.
This post was last edited by oatobnus on 2010-4-27 at 12:51. There are various ways to start a sequential empty table. There are six types: I: Executes B upon initial startup or restart of I:FCS; B: Starts and executes only during the initial cold startup of FCS; TC: Checks the conditional rules at each scanning cycle, and performs an action once when the condition changes from not being met to being met. TE: The conditional rules are checked at each scanning cycle; as long as the conditions are met, the corresponding actions are executed at every scanning cycle. OC: The called scanning cycle checks the conditional rules, and an operation is performed once when the condition changes from not being true to being true. OE: The called scanning cycle checks the conditional rules; as long as the conditions are met, the corresponding action is executed. Take a look at the startup method selected in your sequence control table.
Personal opinion: I think the logic behind your pump isn’t complete. What you do in the sequence table are the conditions; you need to include these conditions in the logic for starting and stopping the pumps. Add an AND gate here to connect it with the on-site manual switches, and then proceed to the electrical addresses for starting and stopping the pumps. In this way, even if you start the pump on-site, the conditions are not met (MV