Analog I/O
- Last UpdatedMar 10, 2020
- 2 minute read
Complete the analog portion of the cross-reference table by associating Foxboro block parameters with model object parameters (also called model variables).
|
Block |
Type |
Description |
Process Variable |
|---|---|---|---|
|
TNK_LVL |
AIN |
Tank Level |
TTL1.L |
|
LVL_CTRL_DMD |
AOUT |
Tank Level Control Valve Demand |
VTL1.OP |
|
DISCH_DMD |
AOUT |
Pump Discharge Valve Demand |
VTL2.OP |
Row 1: Leave the To Symbol as DEMO:TNK_LVL.POINT and edit the From Symbol to be TTL1.L.
Row 2: Edit the To Symbol to be VTL1.OP. Since the value of DEMO:LVL_CTRL_DMD.OUT ranges from 0 to 100 and the value of VTL1.OP ranges from 0 to 1, a conversion factor must be used. This is assigned using the Equation field. In this example, we cut DEMO:LVL_CTRL_DMD.OUT from the From Symbol field and paste it in the Equation field. Add a multiplier of 0.01. The final equation should read DEMO:LVL_CTRL_DMD.OUT * 0.01.
Row 3: Edit the To Symbol field to read VTL2.OP. Again, move the From Symbol DEMO:DISCH_DMD.OUT to the Equation field adding a multiplier of 0.01.
Note: When using the Cross Reference Equation field, the symbol name must begin with a letter. If the Symbol name begins with a number (Example: "1"), place quotes around the Symbol as shown below.
"1BMS:LVL_CTRL_DMD.POINT" * 0.01
Note: The value of the tank level can be cast from meters to feet by placing "{ft}" after the DYNSIM process variable.
