Regarding the commissioning of cascade connection
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For putting the cascade control into operation, first set the secondary circuit to automatic mode and the primary circuit to automatic mode as well; then switch the secondary circuit to cascade mode. My question is: what will be the consequences if the primary circuit is set to automatic mode directly and the secondary circuit is set to cascade mode? Can it have a regulating effect?
You can give it a try. . . . The idea is quite bold
Generally, systems have settings in place that prevent them from being used; if it’s possible to use them anyway, you can give it a try； If the parameters are set properly and the process is stable, there should be no major issues; this is for reference only ；
We switched the main circuit to manual mode and the auxiliary circuit to automatic mode; we found that the interference was too high. By switching the auxiliary circuit to cascade mode without turning off the main circuit, everything worked fine. Hehe… Some people aren’t even willing to try that
It should be to set the follow-up value first and then the fixed value; I remember it being that way. If it’s for debugging, you can give it a try
I think switching the main circuit to automatic mode and the secondary circuit to cascade mode right from the start will cause significant fluctuations. Generally, the secondary circuit is manually set to a value close to the operational value for production, after which it is switched to automatic mode; then the primary circuit operates automatically, and finally the cascade control is activated for the secondary circuit.
Give it a try; what’s there to it? It’s unstable either way
The value of the secondary loop needs to be adjusted to the desired level, or at least to a value that remains stable for a while, with not too large a difference. This way, it’s possible to implement cascade control; once the secondary loop reaches the required value, the value of the primary loop will also be fairly close to that value. By connecting the secondary loop in this manner, large differences in values won’t cause excessive adjustments, which in turn wouldn’t lead to significant fluctuations in both the primary and secondary loops. In some cases, the secondary loop may not be able to be adjusted to the desired level, resulting in an increasing deviation, and in such situations, cascade control loses its meaning
Once the secondary loop reaches the set value, CAS cascade control should be activated; then, once the primary loop reaches the set value, AUTO mode should be engaged. This is for Honeywell DCS systems – I’m not sure if other systems work in the same way
At the moment the main controller is set to automatic, the secondary controller is still in manual mode, and the secondary circuit is open. The system cannot be adjusted.