Cascade control, how to operate it
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I. PICA3001 serves as a pressure alarm, with the SV value set at 0.8 MPa (usually ranging from 0.73 to 0.736). The opening degrees of valves PV3001-1 and PV3001-2 are adjusted in a cascade manner for pressure control. To ensure stability, manual control is used; could those who are more experienced tell me how to switch to automatic control without affecting normal operation under the current conditions?
This post was last edited by jlshnlhj on 2020-3-22 at 11:58. First, clarify the relationship between the SPLIT (in C) module and PV3001-1, PV3001-2 (both are in M). Since the configuration cannot be seen, the suggestions that follow are not reliable. It is also necessary to find out if there are any process requirements or restrictions regarding the PV3001-1 and PV3001-2 switches.
The PICA3001 output is split to generate two signals, which are sent to PV3001-1 and PV3001-2 respectively; no secondary controller is visible, and this diagram appears to represent a pressure range control alarm system.
This is a split journey. It’s fine to use manual control for valve 2 and just control valve 1
Could you add a contact method so I can ask questions?
Could you add a contact method so I can ask questions?
It is a pressure range control alarm system; if the SV and PV values are set to the same value and the mode is set to automatic, valves 1 and 2 will not operate
It is a pressure range control alarm system; if the SV and PV values are set to the same value and the mode is set to automatic, valves 1 and 2 will not operate
When the SV and PV values are set the same, the controller deviation is zero, and of course the two control valves will not move.
This post was last edited by jlshnlhj on 2020-3-24 at 11:12. I’ve already told you: both PV3001-1 and PV3001-2 are set to M (i.e., manual), and you still don’t understand. By the way, do you see “IMAN” to the right of “MAN” on the instrument panel? That stands for In the initialization manual mode (with the back circuit disconnected). The SPLIT module also has a switch SW that controls the connection between IN and OUT1/OUT2; moreover, it’s possible to adjust the range for these two outputs. Therefore, it’s necessary to understand whether there are any process-related requirements regarding the operation of the PV3001-1 (located at M) and PV3001-2 (also at M) valves – one with a 40% setting and the other with a 48% setting. There is likely an MLD module in each case when the device is in the M state. It’s also possible that ST16 is used to manage the status of the instruments in the background. Given that you may not be very familiar with the Yokogawa system and since the device is currently operating normally, it’s not recommended that you attempt to make any changes. The one who tied the knot must be the one to untie it; let the instrument configuration be redeployed. Again, the same thing: without being able to see the configuration, any suggestions that follow are not reliable. It might even mislead you into a trap. In fact, if one is familiar with the Yokogawa system and the circuit has been in normal operation before (including with the PID settings already adjusted), the warning messages provided can be used for inspection; this allows the circuit to be brought out of IMAN mode. Moreover, even when in M mode, the main controller 30PICA3001 can still make the two valves operate. After that, it’s necessary to check the PID parameters and carry out AUT adjustments, adjusting the PID parameters again if needed. The above applies only to the information shown in the flowchart for the first floor.