Honeywell VRX180 Manuale Utente

Being able to diagram a control configuration in terms of function blocks makes it easier to program and 
configure your instrument for its intended process control application.  This function block diagram you 
create can be used as a “construction blue print” to program the instrument.  Each block in the diagram 
relates to a dedicated instrument programming menu in the instrument’s PROGRAM mode. 

What follows are examples where common control configurations are presented along with their function 
block diagrams.  The first example is a simple control arrangement in great detail to help you understand 
function block diagram basics, followed by more sophisticated examples.  Once you understand how to 
diagram function blocks, you will be able to draw a diagram for virtually any control strategy regardless of 
complexity.  Understanding the relationship between such diagrams and the instrument’s programming 
menus is key to successfully mastering the instrument’s many capabilities and features.   

An example of one of the most common and simple control strategies is in Figure 3-11 below. 

GAS

SUPPLY

VALVE

BURNER

FURNACE ZONE

TYPE J THERMOCOUPLE

VALVE

ACTUATOR

4 TO 20 mA

(CAT)

PV    200

SP    500

OUT   83.5%

INSTRUMENT