ANALOG AND DIGITAL INPUT MULTIPLEXER

Owned by Marco Serpelloni
Last updated: Aug 07, 2023
8 min read

Before explore into the description and functions of the various subsystems, it is appropriate to introduce a general concept that applies to the entire REG System, that of the input multiplexer.

Most of the subsystems require the acquisition of temperatures from the system; for example:

  • The Zone subsystem must read the room temperature in order to decide when to heat/cool the zone.

  • The Circuit subsystem must read the flow temperature of a circuit in order to properly manage the mixing valve.

  • The DHW subsystem must read the domestic tank temperature in order to regulate its temperature.

  • The Global Settings subsystem must read the Outdoor Temperature and the information will then be shared with other subsystems to implement other logics (i.e., circuits climatic regulation, or logics for choosing which sources to activate).

Other systems may request the status of a dry contact; for example:

  • The Circuit subsystem can read the status of a dry contact indicating pump blockage.

  • The Zone subsystem can read the status of a dry contact and only activate when the contact is closed

The need then arises to understand where to connect the temperature probe or the dry contact, to which terminals the signal should be physically connected.

The REG System is totally flexible from this point of view, and allows the signal to be connected to whatever input of the boards constituting the system.

ANALOG INPUT SELECTOR

Note

The following examples and images are taken from the RegConfig software, but the same settings can also be made from the LCD display of the REG-DIN-8 board. At all points of the configuration where a temperature (and humidity) value should be (or must be) acquired, there is a drop-down menu which will be illustrated below.

The first, fundamental, distinction is between Passive and Active Probes:

  • Passive Probes

    • Each probes require a direct 2-wire connection between the probe and the board.

    • Each probe uses an analog input of the board REG-DIN-8 or of an expansion board; the total number of passive probes connected to a system is therefore limited by the number of available inputs;

    • Passive probes do not require addressing.

  • Active Probes

    • They use a 4-wire (+,-,A,B) connection from the board and connect the active probes in connection, with an “in-out” wiring.

    • The probes are connected to the BUS terminal of the board, they do not use analog input.

    • The active probes must be addressed, that is each one must be assigned an address that allows the board to communicate with the various active probes connected to the BUS.

Understood the distinction between active and passive probes, it is easy to understand how to configure the parameters that allow you to set the probe for the various zones, systems and outdoor probes:

  • For Passive Probes you set the Board and the Channel of that board to which the probe is connected.

  • For Active Probes you set the BUS address assigned to the probe.

BOARD FIELD

The first part of the field allows you to select from which board to acquire the sensor value from. The drop-down menu lists all the boards that could potentially be present in a system:

therefore from the board REG (REG-DIN-8) to the expansions EXP (REG-EXP-8), IOA and IOB (REG-IOA and REG-IOB).

For the REG-IOC select from IOB 92 to IOB 99 (see REG-IOC data sheet).

It is also possible to use the virtual analogue readings acquired from UGW via Modbus directly from the device being managed (for more information, see the REG-UGW-485 Manual).

In addition to the boards, it possible to directly select the sensor managed via REG bus:

  • AQ – are the air quality sensor _REG-AQ-Sxx (phase-out) and REG-AQ40-Sxx (new ones)

  • T from 160 to 191 – are the temperature and humidity sensor for which only the temperature is to be detected _ REG-TH-Sxx or REG-THL-Sxx

  • TH from 192 to 223 – are the temperature and humidity sensor for which you want to detect both _ REG-TH-Sxx or REG-THL-Sxx

Special values can be selected as will be shown later.

Finally, it is possible to select a Constant and manually enter the desired value, if you want to perform simulations, for examples, and do not have all the sensor connected.

CHANNEL FIELD

If the REG-DIN-8 (REG), REG-EXP-8 (EXP x), REG-IOA, REG-IOB (IOA x / IOB x) or REG-UGW-485 (UGW x) boards have been selected, the Channel field allows you to specify which input, among those available on the selected board type, to use for the reading; the list that appears automatically adapts to the selected board, listing the available channels; for example, in the case of EXP board, 8 channels appear; if an IOA type board is selected, only two channels are displayed:

If the REG-AQ-Sxx (AQ) bus sensor were selected, the channel field must be left at s/set as default, which means that the sensor has no display:

For temperature and humidity sensor (from T160 to TH 223) you must select s/set if they are REG-TH-Sxx sensor, without display and therefore without the possibility of changing setpoint. If c/set is selected, this means that a REG-THL-Sxx sensor with display has been installed. 

Do not use o/set

If SPECIAL is selected, various options are presented:

SENSOR TYPE FIELD

The third field allows you to specify the various types of NTC sensor that REG System boards are capable of acquiring:

  • D = Default, indicates the reference for the board, for the REG System, default = M

  • M = NTC 12kOhm Beta 3977 probes (products with these characteristics are STM/STB/STE/TP-Sxx)

  • A = NTC 10kOhm Beta 3970 probes (products with these characteristics are STA)

  • S = NTC 10kOhm Beta 3435 probes (products with these characteristics are OEM)

  • L = is a linear reading, that is it normalizes the value read from the input from 0 to 100 (it is used in special occasions and to the manufacturer’s instruction)

  • R = Raw value are unprocessed value acquired in specific situations, if needed, as in the case of using the REG2VFS, it is specified in the product data sheet.

DIGITAL INPUT SELECTOR

BOARD FIELD

The first part of the field allows you to select from which board to acquire the digital input status (0 or 1). The drop-down menu lists all the boards that can potentially be present in a system:

then from the REG (REG-DIN-8) board to the expansions EXP (REG-EXP-8), IOA and IOB (REG-IOA and REG-IOB).

For REG-IOC select from IOB 92 to IOB 99 (see REG-IOC data sheet).

It is also possible to use the virtual digital readings acquired by the UGW via Modbus directly from the device being managed (for more information, see the REG-UGW-485 Manual).

At the bottom of the drop-down menu, you can select 3 particular options:

  • VDoutL = corresponds to the states of the digital outputs available in the REG System from zero to 127, for this L stands for Low, that is the lowest values (and their negatives). See VIRTUAL OUTPUT CONFIGURATION

  • VDoutH = corresponds to the states of the digital outputs available in the REG System from 128 to 255, for this H stands for High, that is the highest values (and their negatives). See VIRTUAL OUTPUT CONFIGURATION

  • AlarmDout = corresponds to the alarm states available in the REG System

CHANNEL FIELD

If the REG-DIN-8 (REG), REG-EXP-8 (EXP x), REG-IOA, REG-IOB (IOA x / IOB x) or REG-UGW-485 (UGW x) boards have been selected, the channel field allows you to specify which input, among those available on the selected board type, to use for reading the status; the list that appears automatically adapts to the selected bard type, listing the available channels; for example, in the case of EXP board 8 channels appear; if an IOB type board is selected, only two channels are displayed:

As can be seen from the photos, the digital contact can be taken as either normally open (IAx) or normally closed (/IAx) to satisfy the multiple system requirements.

If  VDout L or VDout H has been chosen, the channel field will be populated according to the setting that has been made except the first 13 digital outputs:

If AlarmDout has been chosen, the channel field will be populated with all the alarms available within the REG System setting:

Obviously, they will work or not depending on the program of the specific case.