SIEMENS SIMATIC S7 + WINCC
Bottom Dump Valve Control
Bottom Dump Valve Control
The bottom discharge control is performed periodically, being implemented as a function of time, which in the interval and the stipulated period triggers the discharge routine. The bottom discharge valve is also used in interlocking with the high and low level of the boiler steam pipe. Control is performed by measuring the level of the steam pipe through the level transmitter (LT200), which sends a signal to the controller. The controller output signal commands the opening/closing of the bottom discharge valve (XV350). When LT200 has high level, the bottom discharge valve opens in automatic. When LT200 is low, the bottom discharge valve closes automatically regardless of the temporary discharge command.
• Create FB9 FB_VV_DESC Bottom Dump Valve Control.
• Open FB9 for editing. In Component View, double-click on the function block.
• In Interface, enter the input parameters:
| Name | Type | Description | S7_m_c |
|---|---|---|---|
| SPIDF | Int | SP Download Interval Time | True |
| SPAVV | Int | SP Valve Opening Time | True |
• In Interface, enter the output parameters:
| Name | Type | Description | S7_m_c |
|---|---|---|---|
| TDIDF | Int | Elapsed Time Interval between Downloads | True |
| CA | Bool | Automatic command | True |
• In Interface, enter the IN_OUT parameters:
| Name | Type | Description | S7_m_c |
|---|---|---|---|
| AM | Bool | Valve Auto/Manual |
• In Interface, enter the STAT parameters:
| Name | Type |
|---|---|
| TMR1 | TON |
| DI1SPIDF | DInt |
| DI2SPIDF | DInt |
| XSPIDF | Time |
| DI_MINUTO | DInt |
| START | Bool |
| P1 | Bool |
| P2 | Bool |
| P3 | Bool |
| DI1TDIDF | DInt |
| DI2TDIDF | DInt |
| XTDIDF | Time |
| DI1SPAVV | DInt |
| DI2SPAVV | DInt |
| XSPAVV | Time |
| TMR2 | TON |
| DI_SEGUNDO | DInt |
• Conversion of the SP Interval between Downloads, from the int type (in minutes in the supervisory) to the time type (milliseconds).
• Conversion of Elapsed Time between Downloads, from time type (milliseconds) to int type (in minutes in the supervisory).
• Conversion of SP Dump Valve Opening, from the int type (in seconds in the supervisory) to the time type (milliseconds).
• Countdown time interval between downloads (time the valve is closed).
• Step 1 - Open the bottom dump valve.
• Step 2 - Opening time of the bottom dump valve.
• Step 3 - Close the bottom dump valve. Start = 0 starts counting time between downloads.
• In manual, reset the parameters.
• Open VVS_ON_OFF and insert FB_VV_DESC below the VV350.
| CTR_XV350 | FB_VV_DESC | DB61 |
• Select Operator Control and Monitoring for DB61 CTR_XV350.
• Compile AS and OS.
• Create PID frontal for Bottom Dump Valve in Controles.pdl.
