Honeywell VRX180 user manual Function block parameter, Output code

Programming and Operating Concepts

Function block parameter

A function block parameter’s data is contained within the block. When you are programming a function block and are not given a choice of PARM, you are programming a function block parameter. Typical choices when programming a function block parameter are NONE, OFF, any numerical value, or a list of options for the parameter, but not PARM. See Figure 3-7.

For example, to program an Alarm function block’s ALARM ACTION, you select from a list of choices: NONE, LOW, HIGH, DEV, LRATE, HRATE.

Other function block parameters are an Analog Input’s RANGE LOW and RANGE HIGH, where you specify the voltage range or temperature range.

Output code

An output code is the result of the function block's operations on the input parameters and function block parameters. It is designated by one of the two-character output codes shown in Table 3-4. An output code can be programmed to be the input to one or several other function blocks. See Figure 3-7.

Output codes are either discrete (can be on or off) or analog (numerical value). For example, DI1 OS is the output status of Discrete Input #1: on or off. AI1 OV is the output value of Analog Input #1: a voltage or temperature. Therefore, a discrete input parameter must be programmed with only a discrete output code, and an analog input parameter must be programmed with only an analog output code.

ATTENTION

The function block SYSTEM PARAMETER, abbreviated SY, does not have input parameters or function block parameters like the other function blocks; SY produces output codes only. These output codes, shown in Table 3-4, are mostly values or states that indicate the status of system-wide parameters. For example, if any Alarm function block’s output status is ON, the SY function block’s AG (alarm global) output code is also ON.

Another example is the SY F1 output code, which produces a quick ON-to-OFF discrete signal when the F1 key is pressed. This SY F1 can be used as a trigger to another action. For example, to allow an operator to start the Profile or reset the Totalizer by pressing the F1 key, you can program a Setpoint Profile’s Start parameter or a Totalizer’s Reset parameter with SY F1.

52 Video Recorder – User Manual