Fidelix multiDISPLAY FX-HP Programming Manual Download

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Fidelix FX-RP multiDISPLAY

Programming manual

page 33 of 38

How to work with input/output registers

Each display point (POINT1, POINT2, ..., POINT250) has 6 registers attributed to it (3 input and 3 output).
When making graphics, you can assign a unit and a divider (the number of decimals) to each point. You can

also set these attributes from your master, if that is desirable, into register 0, 3, ..., 747. This feature is currently

no longer frequently used. Its original purpose (during development there were only 50 display points) was to

set the point type dynamically; having only 1 page, "looping through" different values. Currently that register is

set at 0F99x16 (3993) if it has not been written over by the Modbus master.
Each point has an "info" register (1000, 1003, ..., 1747) which indicates if the point’s value has been set from

the display (=1). This is useful when you allow a user to enter a value (you ticked the “controller set value” box

in the EditPoint dialog box in the graphics editor) and you have not defined #MIN and/or #MAX on the graphics,

but want to validate the input, or simply monitor this register to detect changes in setpoints. In this case you can

use the "Parameters, Divider, Unit" registers (0, 3, ..., 747) to initially hide the user input value, validate it in your

master and only then write it to the display (bits 7 and 8 of the most significant byte, see

Input Data

A value set from the display will be saved into registers 1001+1002, 1004+1005, ..., 1748+1749. At the same

time, it will set register 1000, 1003, ..., 1747 to "1", indicating a point's value has been changed locally. If the

master reads these values, it can “confirm” them by writing the same value into registers 1+2, 4+5, ..., 748+749.

Once that has been done, the display will set the info register (1000, 1003, ..., 1747) back to 0, again notifying

the Modbus master that all points and values have been properly synchronized.
A 4-and-a-half-minute video is available on Youtube to clarify this process:

https://youtu.be/tEushV8ugsA

This rather complex process is however not always necessary. Actually, in most cases, we don't use it when not

working with the Fidelix multi24 controller (where all of these functionalities are embedded into two functions

GetDisplayPointF and SetDisplayPointF). Using a third party controller, the easiest way is to just write directly

into registers 1001+1002, 1004+1005, ..., 1748+1749, overwriting any value from the display when the point

value is editable from both the multiDISPLAY and the Modbus master.

TL;DR:

In most cases, you will have a very distinct separation between the points you want to read and the ones

you want to write and only select “controller set value” for those points you will set from the multiDISPLAY. Read

those from registers 1001+1002, 1004+1005 etc and write “read only” values on the multiDISPLAY that are

being written by the Modbus master into registers 1+2, 4+5 etc.

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