Honeywell VRX180 Components of function blocks, Alarm 1 Function Block Components Input parameter

Programming and Operating Concepts

3.10 Components of function blocks

The three components of a function block are:

Input parameter(s)

Function block parameter(s)

Output parameter(s).

Figure 3-7 shows the function block Alarm #1’s components.

Al a rm 1 F unc ti on Bl oc k

Functi on block parameter	ALARM ACTION (Select H igh, Low, Dev , LRate, H Rate)
Functi on block parameter	IN D ECI MAL POS (Selec t input decimal pos ition)
In put param ete r	IN PUT (Select OFF , Numb er, or PARM)
Input parameter	SETPOINT (Select OFF, Number or PARM)
Input parameter	COMPARE POINT (Select OFF , Number, or PARM)
Functi on block parameter	HY STERESIS (Select OFF or Numb er)
Functi on block parameter	DELAY TIME (Select OFF or Number)

Outp ut paramet ers

AL 1 OS (Alarm s tate)

AL 1 S2 (Compare point of

De vi ation alarm o nly )

AL 1 PV (Value of alarm' s IN PUT)

Figure 3-7 Alarm 1 Function Block Components

Input parameter

A function block's input parameter can be configured to be OFF, a number, or it can receive its data from outside the block from another block's output codes. These output codes are shown in Table 3-4. That is, an input parameter is any menu item that can be programmed as (connected to) one of these output codes. These output codes are grouped under the menu choice PARM. When you are programming a function block and one of your choices is PARM, you know you are programming an input parameter. See Figure 3-7.

For example, suppose you are programming an alarm function block. One of the alarm’s menu items is INPUT, which specifies which point will be monitored for an alarm condition. One of the choices for the INPUT is PARM, which lets you connect the INPUT to one of the output codes in Table 3-4. Therefore, the INPUT is an input parameter because it receives its data from another function block.

Some function blocks can have multiple input parameters. For example, an Alarm function block has an INPUT and a SETPOINT, both of which can be connected to other function blocks.

Discrete Input function blocks have no input parameters; that is, they have no inputs that can be connected to another block’s output codes.

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