2
0
1
8
-0
7
50
Channel-Related Parameters for the Valve Coupler Modes
8
Channel-Related Parameters for the Valve Coupler Modes
This section describes the channel-related parameters and basic information, regarding the
following aspects:
■
Setpoint inversion
■
Modes of operation
■
Functional parameters
■
Diagnostic parameters
8.1
Use of Setpoint Variables SP_D and RIN_D
The setpoint value controls the position of the final control element, for example a valve or a
pilot valve if available.
The setpoint value is 0 or 1 (1 byte). The set position may be either "closed" or "open".
Thus, the MIO needs the information if in the "open" valve position the current is ON or OFF for
the auxiliary valve. This is specified by the Actuator Fail Action parameter, see chapter 8.3.1.
The Actuator Fail Action parameter determines in which state the valve is OFF. In this context,
the Invert Setpoint parameter determines the values for the set position.
If the Invert Setpoint parameter is set to "OFF", the setpoint value is not inverted. The setpoint
value "0" controls the valve in the "closed" position. The setpoint value 1 controls the valve in
the "open" position.
If the Invert Setpoint parameter is set to "ON", the coding of the setpoint value is inverted. That
means, the setpoint value "0" controls the valve in the "open" position. The setpoint value 1
controls the valve in the "closed" position.
Note!
Behavior of the Setpoint Value
The setpoint value works contrary to a number of conventional devices, where, e. g., the value
"0" stands for "valve current OFF" and the value "1" stands for "valve current ON".
Example!
Example 1: "Invert Setpoint" is OFF
■
The Actuator Fail Action parameter is set to "closed".
■
The actuator moves into the closed position ("closed"), when the current of the valve is
OFF.
■
If the setpoint value is "0" ("closed"), the auxiliary valve is not triggered.
=> In this case, "0" means "current OFF".
Example!
Example 2: "Invert Setpoint" is OFF
■
The Actuator Fail Action parameter is set to "open".
■
The actuator moves into the open position ("open"), when the current of the auxiliary valve
is OFF.
■
If the setpoint value is "0" ("closed"), the auxiliary valve is triggered.
=> In this case, "0" means "current ON".
