Use 'variables'. Variables can be entered from the Operator interface or with the 'write variable' function block.
You don't "read the address" to get a variable value; unless a Modbus Master is reading the HC900 as a Modbus slave. Rather, you read the variable by using the tag name that you gave the variable. That tagged variable remains whatever you establish it, until you change it. The write variable function block below) has an enable pin, so you can selectively time when you "write the variable".
To create a variable:
Right Click On Unconnected Function Block pins, when you drop one of these items (from the list) it automatically connects to the pin you right-clicked on.
- Analog Variable
- Digital Variable
See an example where ALM SP is a variable feeding the RSP (remote setpoint) of an alarm block on page 66 (ALM alarm function block) of the Function block reference Guide.
Also see the WVAR Write Variable Function Block: (Text below copied from the Function block manual)
Description: the WVAR label stands for Write Variable. This block is part of the Auxiliary category.
Function
Writes a new value to a selected Variable number.
Select the target variable number from the specific function block reference data and enter it in the appropriate field in the “Write Variable Number” dialog box.
• If EN is ON, then the Variable selected is set to the value of X.
(For example: X = a constant value)
Inputs
X = Value to be written to the selected variable
EN = Enable command
Target write variable number
Double click on the function block to access the “Write Variable Number” dialog box.
Enter the Target Variable number in the appropriate field. Selections are from 1 to 600.
Dan
