FR2764420A1 - Master-slave command system for central heating installations - Google Patents

Abstract

The master to slave command system has a master command unit (10) which controls a number of slave units (2-1,2-2,...2-n) using a single wire connection (30) to each unit. A process is generated prior to use which provides a selection of command orders. These command orders are then transmitted following a set of digital bit sequences, which are only used for command orders.

Description

 The present invention relates to a method for controlling slave devices from a master unit. Such a method is for example used in an electric heating installation where electric heating devices, such as convectors, are controlled by a control and regulation unit. It could be an installation in which the slave devices are also electric air conditioning devices controlled by a master unit.

 Such control methods are already known and we will cite one which is known to those skilled in the art under the name of "pilot wire control". For the implementation of this method, the control orders are transmitted from said master unit to said devices by continuously transmitting an electrical signal on a single electrical wire, called a pilot wire. With this type of process, four control orders can be transmitted according to the form of the transmitted signal which is constructed from the phase of the network of the sector used to supply said electrical devices. For example, in the case of the control of electric heaters, such as convectors, the four orders correspond to four operating modes. fi are the so-called comfort, economic, stop and frost protection modes. The signals then transmitted on the pilot wire are then respectively the following; no signal on the pilot wire for comfort mode, the two phase alternations for the economic mode, the only positive phase alternations for the stop mode and the only negative alternations for the frost-free operating mode.

 With the development of electronics and IT, it is now possible to implement master units intended for relatively complex device programming, at low cost. As a result, today there is a need for methods of controlling devices with a number of orders greater than four orders. However, the problem with the creation of these new control methods is their compatibility with the control methods of previous generations.

Compatibility means that the slave devices of the old generation can be controlled without modification by a master control unit of the new generation and that conversely, devices of the new generation can be controlled by a unit. control of the old generation. In these two cases, the devices will only be able to operate in the older generation modes and this is only only in case the devices and
The control units are of the new generation that all the functionalities of the system can be implemented.

 The object of the invention is to propose an order method with a relatively large number of possible commands and which is compatible with the command method with a method, known as the previous generation method, according to which the command orders are transmitted from said master unit to said devices continuously.

 To achieve this object, a method according to the invention is characterized in that it consists in reversing, for predetermined durations, the control orders issued according to the previous generation method so as to form at least one bit, said one or more bits being then only used for the transmission of command orders.

 In the case where the control orders are transmitted to said slave devices in the form of a signal constructed from the phase of the network used to supply said devices, the duration of the reversals is advantageously multiple of the period of said network.

 According to another characteristic of the invention, it consists in reversing the control orders issued according to the previous generation method at least twice, a first time so as to create a first bit, called the start bit, and the other times of so as to create other bits, called information bits. Said start bit is advantageously separated from the single or from the first information bit of a rest period during which there is no inversion of the control orders issued according to the previous generation method.

 According to another characteristic of the invention, it consists in forming a start bit and a single information bit. The information bit is advantageously transmitted at a predetermined duration after said start bit from a number of possible durations. This duration is advantageously a multiple of a predetermined duration, for example the network period.

 According to another characteristic of the invention, the duration of the start bit makes it possible to identify the nature of the information resulting from the subsequent information bit or bits.

The present invention also relates to the application of said method to an installation whose slave devices are electrical heating or air conditioning devices. In this type of device, each control order issued according to said previous generation method is used to position said devices in one of the operating modes known as stop, frost-free, economical or comfort. According to
The invention, the reversals of so-called stop, frost-free, economic or comfort control orders issued according to the prior generation method and provided for by the method of the invention, result in the signals corresponding respectively to the frost-free orders, stop, comfort and economy.

The characteristics of the invention mentioned above, as well as others, will appear more clearly on reading the following description of an exemplary embodiment made in relation to the accompanying drawings, among which:
Fig. I is the block diagram of a heating installation to which the method of the invention can be applied,
Fig. 2 is a view explaining the inversion process of the invention,
Fig. 3 is a schematic view of the signals transmitted by a master unit according to the method of the invention,
and Fig. 4 is a time diagram showing the bits resulting from the signals transmitted according to the method of the invention.

 The present invention applies to an installation of the type shown in FIG. 1. This installation is composed of a master control unit 10 supplied by the sector and a plurality of devices to be controlled 21 to 2N also supplied by the sector. The control unit 10 is for example a programmer which transmits control orders to the devices to be controlled 21 to 2N so that they are positioned in a given operating mode. To do this, the devices 21 to 2N are connected to the unit 10 by means of a single wire 30, called the pilot wire.

 In known installations, the command orders are four in number and are transmitted to said devices by continuous emission of a signal on the pilot wire, which is constructed from the phase of the sector used to supply said devices to be controlled. . This signal can be absent, consist of positive and negative alternations of the sector phase, consist of only positive alternations or only negative alternations of the sector phase.

 By way of example, the devices to be controlled are electrical heating or air conditioning devices, such as convectors, which can operate in several different operating modes. For example in the case of devices to be controlled consisting of electrical heating or air conditioning devices, the modes are as follows: off, frost-free, economical and comfortable. When the signal present on the pilot wire consists of positive and negative alternations of the phase of the sector, the devices are controlled in the economic mode. When it consists of only positive half-waves, they are controlled in the stop mode.

When it consists of only negative alternations, they are controlled in the frost-free mode. Finally, if there is no signal, they are controlled in comfort mode.

 According to the invention, to transmit control orders to said devices, the control orders issued according to the method of the previous generation are reversed, for predetermined durations, so as to form at least one bit for each inversion, said bit or said bits being used only for the transmission of said control commands of the method of the invention.

 We call here "bit", an elementary unit of information in the general sense of the term.

 In the case where the slave devices are electric heating devices, said reversals of the stop, frost-free, economic or comfort control orders sent according to the previous generation process result in the signals corresponding respectively to the frost-free, stop orders , comfort and economy. There is shown in FIG. 2, on the one hand on the line marked I, the different possible forms of signals transmitted according to a method of the previous generation by control by pilot wire and, on the other hand on the line marked II, the same signals which have been inverted within the meaning of the invention. It can be seen that, in the absence of a signal, a full-wave signal is matched by inversion and, to a full-wave signal, an absence of signal. Only positive alternations are made to correspond to negative alternations and vice versa.

 This way of proceeding will make it possible to obtain the desired compatibility, insofar as the devices to be controlled of the old generation will be controlled by the signals emitted by the method of the invention but, these being of short duration, do not will be only very slightly disturbed in their functioning over time. Thus, they will be able to function properly even with a new generation maltre unit. Likewise, new generation devices will also be able to receive signals from an older generation master control unit. It will be noted that, necessarily, the master unit of the new generation transmits the bits provided by the method of the invention but also the signals transmitted according to the method of the previous generation.

 According to the preferred embodiment of the invention, the control orders transmitted according to the method of the previous generation are reversed, first once, thus creating a first bit, called the start bit, allowing each device to be controlled to find their way back in time, then at least a second time, creating one or more other bits, called information bits because they together carry control information.

 There is shown in FIG. 2 by way of example, on the one hand on the line marked I, the signal as it is emitted according to the method of the previous generation and as it appears on the pilot wire in the case of a command outside -gel, and, on the other hand, on the line marked II, the signal as it is emitted according to the method of the invention and as it appears on the pilot wire. Note that in the second period, the signal in II is reversed in the sense of the invention for six periods so as to form a start bit marked D.

Then follow three periods where the signal in II is not inverted with respect to that in I forming an idle signal R, then three other periods in which the signal is again inverted so as to form an information bit bo. Again rest periods R.

In the embodiment shown, the duration of the inversions is a multiple of the duration of a period of the phase of the sector, for example three times. Bit duration
D is six, nine or twelve periods (as will be explained below) and the duration of the rest periods R and of the information bit bo is three periods. If To is the duration of a period which is equal to 20ms in the case of a 50 Hz network, the duration of the start bit D is 120ms, 180ms or 240ms, the duration of the information bit is 60ms and the duration of the rest periods R is also 60 ms.

 It will be noted that several bits of information could be transmitted after a given start bit so as to form a frame which would be considered in full by each slave device to know the information transmitted.

According to an alternative embodiment of the invention, a single information bit is transmitted after the start bit, but it is transmitted at a predetermined duration from a possible number, for example sixteen possible. Thus, depending on the position of the information bit relative to the start bit, one piece of information or another can be determined. This duration is for example equal to a multiple of the duration of a rest period. There is shown in FIG. 4 the appearance of the code signal. It is composed of the start bit D, a rest period R necessary to separate the bits from each other and an information bit which, at the line marked I, is the bit bo and which, at the line marked II , is the bit bowls. It will be understood that, in this FIG. 4, the bit bi (i = 1 to n, n number of possible bits) should be sent, in the embodiment shown, at a duration
TRX (i + 1) of the start bit D, TR, being the duration of a rest period.

 According to another characteristic of the invention, the duration of the start bit makes it possible to identify the nature of the information bit determining the operating mode of the controlled device. This characteristic makes it possible to further increase the number of information transmitted.

 The following description relates to an application of an embodiment of the method of the invention to the control of electric heating or air conditioning devices. It will be considered that a device to be controlled has received a bit of information bi as soon as the signal present on its pilot wire consisted of a start bit D and a bit bit.

 Three durations of the start bit have been proposed corresponding to three operating modes which are explained below. These three durations are for example of six, twelve and eighteen alternations respectively, that is, for a network at 50 Hz, 120 ms, 180 ms and 240 ms.

 The first operating mode corresponds to a command of the regulation mode of the device controlled. For example, bits b8 to bol4 are used. For example, when the information bit b8 is received, the device to be controlled switches to frost protection mode. When bit b9 is received, it goes into stop mode. On reception of bits b10 to b14, it goes into regulation mode at a temperature corresponding respectively to the setpoint temperatures Tc minus three, minus two, minus one, Tc, and Tc plus one degree.

 Still, in this mode, a bit, for example, bo can be used to control the load shedding of the device considered.

 The second and third operating modes will allow the exchange of digital values for given parameters.

 In particular, the second mode of operation will allow the device to be controlled to determine a parameter whose value will follow. For example, when the bo bit is received, the parameter will be the outside temperature.

 The third operating mode will allow the device to be ordered to receive the value of the parameter which was the subject of the reception in the second previous mode. If the possible information bits are sixteen from bo to blS, the value transmitted will be between 0 and 15. For example, on receipt of the bit bi, the value is i. Several values can be transmitted consecutively one after the other. The first value then constitutes the lowest weight, the following, the following weights. For example to transmit the value A5h in hexadecimal the first value is the value 5h and the second Ah.

Claims (9)

 1) Method for controlling slave devices from a master unit, said method being compatible with a method, known as an earlier generation method, according to which control orders are transmitted from said master unit to said devices continuously, characterized in that it consists in inverting, for predetermined durations, the control orders transmitted according to the previous generation method so as to form at least one bit, said one or more bits being then only used for the transmission of control orders.  2) The control method according to claim 1, wherein the control orders are transmitted to said slave devices in the form of a signal constructed from the phase of the network used to power said devices, characterized in that the duration inversions is a multiple of the period of said network.  3) control method according to claim 1 or 2, characterized in that it consists in reversing the control orders issued according to the previous generation method at least twice, a first time so as to create a first bit, called bit start, and the other times so as to create other bits, called bits of information.  4) control method according to claim 3, characterized in that said start bit is separated from the single or from the first information bit of a rest period during which there is no inversion of the control orders issued according to the previous generation process.  5) A control method according to claim 3 or 4, characterized in that it consists in forming a start bit and a single information bit.  6) A control method according to claim 5, characterized in that it consists in transmitting the information bit at a predetermined duration after said start bit from a number of possible durations.  7) A control method according to claim 6, characterized in that said predetermined duration is a multiple of a predetermined duration, for example the network period.  8) A control method according to one of claims 2 to 7, characterized in that the duration of the start bit makes it possible to identify the nature of the information resulting from the subsequent information bit or bits.  9) Method according to one of the preceding claims applied to an installation in which the slave devices are electric heating or air conditioning devices, each control order issued according to said previous generation method serving to position said devices in one of the operating modes. so-called stop, frost-free, economical or comfortable, characterized in that said reversals  so-called stop, frost-free, economic or comfort control orders issued according to the  previous generation process result in the corresponding signals  respectively to frost, stop, comfort and economic orders.