We are using mark-vie for combined steam turbine control. After commission, we have some problem in TMR Servo Valve control. Three lvdt are installed in one valve and Three Servo Regulators control the servo valve. There are cv#1, #2 which have same parameters in our control system. Only cv#1 have been fluctuated with 3% range (ex> demand: 40% , feedback: 37%~43%) does not only just feed back also actual valve fluctuating. so when unstable condtion Electrical Hydrauric Control Line are vibrated criticaly.
FIRST: we already changed servo valve to new one, but problem still exist.
SERVO VALVE: REXROTH HYDRAULICS: 4WS2EM, nominal current per coil 30ma, resistance per coil 85ohm)
second : Althought we don't think there are some problem in our lvdts. we changed a one lvdt to new one because of both low probability in lvdt malfuction and our system with tmr control, but problem still exist
third: that is very interesting.
after we disconnected the R core from TMR servo control, Valve status back to normal
so we tested other core S,T one by one. Results are same above.
R(X)S(0)T(0)--> VALVE STATUS IS GOOD
R(0)S(X)T(0)--> VALVE STATUS IS GOOD
R(0)S(0)T(X)--> VALVE STATUS IS GOOD
R(0)S(0)T(0)--> VALVE STATUS IS BAD(FLUCTUATED)
fourth: in normal operation our cv#1#2 are full open status. At that time, Valve is not moving any more (demand over 100%), but in other positions (20%, 30%, 50%, 70%..). During start up , we suffer the problem.
Could you let me know how to solve this problem.
Now i consider the pvso regulator gain adjust, but i want more information about this.
FIRST: we already changed servo valve to new one, but problem still exist.
SERVO VALVE: REXROTH HYDRAULICS: 4WS2EM, nominal current per coil 30ma, resistance per coil 85ohm)
second : Althought we don't think there are some problem in our lvdts. we changed a one lvdt to new one because of both low probability in lvdt malfuction and our system with tmr control, but problem still exist
third: that is very interesting.
after we disconnected the R core from TMR servo control, Valve status back to normal
so we tested other core S,T one by one. Results are same above.
R(X)S(0)T(0)--> VALVE STATUS IS GOOD
R(0)S(X)T(0)--> VALVE STATUS IS GOOD
R(0)S(0)T(X)--> VALVE STATUS IS GOOD
R(0)S(0)T(0)--> VALVE STATUS IS BAD(FLUCTUATED)
fourth: in normal operation our cv#1#2 are full open status. At that time, Valve is not moving any more (demand over 100%), but in other positions (20%, 30%, 50%, 70%..). During start up , we suffer the problem.
Could you let me know how to solve this problem.
Now i consider the pvso regulator gain adjust, but i want more information about this.