JP2011052936A - Communication method for air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means enabling prompt transmission in a node in which telegraph transmission is delayed, in an air conditioner in which outdoor and indoor units in a plurality of refrigerant systems are interconnected through one transmission line for communications. <P>SOLUTION: In a communication means avoiding collision by setting a random value in transmission waiting time T1 before transmission, by reducing a maximum value of the transmission waiting time T1 along with passage of time after completion of previous normal transmission, priority to the node in which telegraph transmission is delayed is increased. By resetting the priority immediately after completion of normal transmission and setting the maximum value of the transmission waiting time T1 in accordance with communication traffic, competition of transmission rights and collision of transmitted telegraph are avoided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an outdoor unit of a plurality of refrigerant systems, and a communication method of an air conditioning system in which communication is performed by connecting indoor units with a transmission line.

  For example, in the case of an air conditioning system in which indoor units or the like of a plurality of air conditioners are arranged in a building or the like, a configuration in which various devices (nodes) such as outdoor units, indoor units, and centralized devices are connected by transmission lines is adopted. . These devices are each controlled in an integrated manner by transmitting and receiving messages. As the number of devices connected to such an air conditioning system increases, the number, frequency, and probability of collision of each telegram increases, and it becomes a state where it cannot be substantially controlled. As a method for avoiding excessive collisions and reducing communication traffic, for example, a technique as disclosed in Patent Document 1 is known.

  In Patent Literature 1, the collision probability is determined by the number of telegram transmission factors occurring at the same time and the minimum value and the maximum value width of the transmission waiting time T1 randomly given to each node. For this reason, increasing the maximum value of the transmission waiting time T1 widens the selection range, and reduces the probability that a plurality of nodes transmit at the same timing.

  However, if the maximum value of the transmission waiting time T1 is too large, the waiting time increases even in a state where there is little collision. Therefore, by appropriately setting the maximum value of the transmission waiting time T1 according to the size of communication traffic, it is possible to avoid the phenomenon of repeated retransmission due to collision while suppressing the delay due to transmission waiting.

JP-A-6-169912

  However, in Patent Document 1, there is a problem that the standby time of a node that cannot acquire a transmission right due to loss of contention increases when there are many transmission factors that occur at the same time even in a situation where communication can be performed with few collisions. .

  In addition, if the standby state continues for a long time, a message transmission factor may occur again at a node that has completed normal transmission during that time, and may participate in a transmission right conflict. In this case, there is a possibility that contention for transmission rights of other nodes will be prolonged. In such a situation, if a node that cannot transmit a message indefinitely appears, the node can no longer be controlled. Furthermore, the node may be diagnosed as a failure. If such a state where a message cannot be transmitted / received continues, there is a possibility that the communication will be interrupted and the operation may be stopped. Therefore, such a node needs to be able to transmit with priority.

  An object of the present invention is to provide an air conditioning system in which at least a predetermined node can quickly transmit a message.

The object of the present invention is as follows.
In a communication method of an air conditioning system controlled by connecting nodes such as outdoor units and indoor units of a plurality of refrigerant systems through a single transmission line and communicating with each node,
In order for a node to send a message with priority,
The node is
Measure the non-transmission time, which is the time after the normal transmission of the message is completed,
This is achieved by setting the maximum value of the transmission waiting time shorter as the non-transmission time becomes longer.

  According to the present invention, at least a predetermined node can quickly transmit a message.

Schematic which shows the communication connection Example of the air conditioner of this invention. The schematic which simplified FIG. The sequence diagram which shows the example of communication at the time of the message transmission by a conventional system. The time chart of the maximum value of transmission waiting time T1. The sequence diagram which shows the example of communication at the time of the message transmission in a present Example. The figure which shows the relationship between a refrigerant | coolant system | strain and a transmission line. The figure which shows the example of wiring.

  Embodiments of the present invention will be described with reference to the drawings.

  1 and 6 show a connection form of a multi-room air conditioner according to an embodiment of the present invention.

  The air conditioning system of the present embodiment includes multiple types of outdoor units 21 to 24, multiple types of indoor units 31 to 3n, a centralized control device 4, and a common transmission line 1. To centrally control these devices (nodes) installed in a distributed manner, a transmission line 1 transmits and receives a message.

  This system is a method of wiring control wiring between indoor units across a plurality of refrigerant systems, and the number of indoor units to be connected is 100 or more. Thus, the number of installed air conditioners is increasing with the increase in large-scale properties. Since there is no restriction on the order of units to be connected and the number of branches of wiring, wiring can be performed freely according to the installation location of the units. However, there are no branches in FIGS.

  21 and 22 are outdoor units for the building multi, 22 is an outdoor unit for the store, and 24 is an outdoor unit for the gas heat pump air conditioner (GHP). In this system, the transmission line can be wired over the transmission line 1 with no distinction between refrigerant systems (FIG. 6). The hatched line represents the refrigerant pipe.

  In this system, a connection method as shown in FIG. 7 is possible. However, loop wiring cannot be done in any case. As (a), all units can be connected via a crossover. As (b), it is possible to branch the crossover line halfway. The figure shows two branches. In this case, since the number of branches is not limited, for example, it is suitable for the case where the connecting lines are connected in units of floors. As (c), after wiring the refrigerant system, the outdoor unit is crossed and wired.

  FIG. 2 is a simplified version of FIG. 1, and nodes Nm (m = 1, 2, 3,...) Represent the outdoor units 21 to 24 and the indoor unit 3n.

  By unifying the communication system and wiring system for multi-air conditioners for buildings, air conditioners for shops and offices, and GHP air conditioners, these air conditioners can be mixed on the same system without using adapters or dedicated connectors. Further, the central control device 4 can be installed at an arbitrary position of this system.

Thus, using a common transmission line is easy to work. On the other hand, as the number of nodes increases, transmission opportunities within the same transmission path increase, and transmission factors may occur simultaneously at a plurality of nodes. This is because only one message is allowed on the transmission line 1. The node Nm can transmit a message itself only when there is no carrier (message) on the transmission line 1.
In order to transmit a message, a maximum time of about 50 [ms] is required.

When transmitting and receiving a telegram in such an air conditioning system, for example, in the CSMA (Carrier Sense Multiple Access) method, the following procedure is performed.
(1) Each node detects the presence or absence of a message (carrier) on the transmission line.
(2) When a carrier is detected, each node stands by.
(3) If no carrier is detected, telegram transmission is possible, but in order to avoid collision caused by other nodes transmitting at the same timing, a random transmission waiting time T1 is set for each node. .
(4) If no carrier is detected continuously for the time T1, the node starts transmission of a telegram.
(5) The node performs collision detection during message transmission.
(6) If a collision is detected in the node, transmission of the message is interrupted, and a retransmission wait time T2 having a random value is set.
(7) In the node, when no carrier is detected continuously for the time T2, the node starts transmission of a message.

  Node in which the shortest transmission waiting time T1 is selected between nodes competing for transmission rights because all the single nodes (on the transmission line 1) shown in the figure perform carrier detection simultaneously in the same transmission path. Acquires the transmission right and starts transmission. When the node that has acquired the transmission right starts transmission, the other nodes detect it as a carrier. Each node that detects this waits until no carrier detection occurs, and then a new transmission waiting time is set. When a plurality of nodes select the same transmission waiting time T1, transmissions are started at the same time, and telegram collision occurs. When a collision occurs, the message is retransmitted. As the number of nodes in the transmission path and the transmission factor increase, the collision probability increases, and repetition of collision and retransmission (congestion) may occur endlessly. Therefore, as described later, the waiting time is set short after the collision.

  When the outdoor unit does not receive a message from the indoor unit for a predetermined time (for example, 100 [s]), the outdoor unit regards the indoor unit as abnormal. Therefore, the indoor unit transmits a message to the outdoor unit if it does not transmit a message for a predetermined time (for example, 30 [s]) from the completion of the previous transmission. It takes about 10 [ms] to transmit this message.

  If these messages are on the transmission line 1, the other nodes cannot transmit the message, and the transmission line 1 is congested. This is expressed by the degree of congestion. The congestion level of the transmission path is calculated by measuring the time (transmission path usage rate) that the carrier exists per unit time. In this system, the degree of congestion is suppressed to a predetermined ratio, that is, less than a predetermined movable rate (for example, 40 [%]). Therefore, it is basically distinguished whether the degree of congestion is high or low with a predetermined mobility as a boundary.

  FIG. 3 is a sequence diagram showing an example of communication at the time of transmitting a message in the conventional method.

  FIG. 3 shows a certain case in which transmission rights compete. While the node N1 is transmitting the telegram 51, the nodes N2 to N4 simultaneously generate transmission factors, and transmission rights contention may occur. Or there may actually be a conflict.

  First, in the first transmission right conflict, the node N4 randomly selects the transmission waiting time 63. That is, the transmission waiting time 63 is set in the node N4. Since this transmission waiting time 63 happens to be shorter than the transmission waiting times 61 and 62 of the other nodes (nodes N2 and N3), the node N4 can acquire the transmission right and start transmitting the telegram 52.

  Next, after the transmission of the telegram 52 by the node N4, the transmission right competes between the node N2 and the node N3. Here, the transmission waiting time 71 is set in the node N2 as described above. Since this transmission waiting time 71 happens to be shorter than the transmission waiting time 72 of the other node (node N3), the node N2 can acquire the transmission right and start transmission of the telegram 53.

  Here, a case where the node N1 again generates a message transmission factor during transmission of the message 53 and participates in a transmission right contention will be described. After transmission of the electronic message 53, as a result of the competition between the node N1 and the node N3, a transmission waiting time 81 is set in the node N1 as described above. Here, N1 can acquire the transmission right and transmit the message 54.

  From the above results, there is a possibility that the node N3 always loses the competition in the range shown in this example, and the state where the message cannot be transmitted continues. For this reason, the following improvements are made.

  FIG. 4 is a time chart of the maximum value of the transmission waiting time T1.

  First, the node that has completed normal transmission resets the priority. That is, the transmission right is transferred to another node. At this time, a waiting time is set according to the transmission path usage rate at the time of normal transmission completion. This setting is performed at the node that has completed normal transmission. When the transmission line usage rate at the time of normal transmission completion is high, the maximum value of the transmission waiting time T1 is set large in order to avoid transmission right contention. When the transmission line usage rate is low, transmission right contention is unlikely to occur. In order to reduce the waiting time until the next transmission, the maximum value of the transmission waiting time T1 is set small.

  In FIG. 4, when a transmission factor occurs immediately after completion of normal transmission of a certain node Nm, for example, when the transmission line usage rate is high (when the degree of congestion is high), the maximum value of the transmission waiting time T1 is A large value is set near T10max, and the priority for transmission of the node is lowered. In other words, when a conflict occurs, the node is set to easily lose the conflict, and the node that sent the message once refrains from sending the message for a while. This is because there are many other nodes that want to send messages.

  Also, when a transmission factor occurs immediately after completion of transmission of a message, for example, when the transmission line usage rate is low, the maximum value of the transmission waiting time T1 is set to around T10 min so as not to greatly reduce the priority for transmission. To do. The reason for this is that even if the priority of the node is kept high, if the transmission line usage rate is low, it is difficult for contention with other nodes to occur. It is because it is thought that there is little property.

  As described above, when the transmission line usage rate when the transmission factor occurs is low, the maximum value of the transmission waiting time T1 is set to be small in order to perform quick transmission, and when the transmission line usage rate when the transmission factor occurs is high, there is a collision. In order to avoid this, the maximum value of the transmission waiting time T1 is set large.

  Also, when there are multiple high priority nodes, if the maximum value of the transmission waiting time T1 is made extremely small, the probability of simultaneous transmission increases and there is a possibility of repeated collisions. Set the lower limit value to limit the selection range of the transmission wait time.

  The size of these transmission waiting times T1 is approximately, but as an example of the case where the transmission path usage rate is relatively low and the highest priority transmission right is given to the collided node, for example, T10min = T1fmin = 15 [ms], T10max = 100 [ms], T10max = 20 [ms].

The transmission waiting time T1 of the node immediately after the normal transmission is completed is T1 = 10 to 20 [ms] in normal times.
It is. If the priority is not given to the time of collision, it may be set to 1 [ms] or more. The same applies to the following cases.

  When the transmission line usage rate is higher than normal, the width of the transmission waiting time T1 increases as the transmission line usage rate increases, and T1 = 10 to 100 [ms] at the maximum. This is because the collision rate is reduced by extremely increasing the width of the waiting time.

  When the transmission line usage rate is lower than normal, the selection width of the transmission waiting time T1 becomes smaller as the transmission line usage rate decreases, and T1 = 10 to 15 [ms] at the minimum. Even if T10min is used because there are few collisions, there is no problem.

At the time of collision, T1 = 1 to 10 [ms]. Therefore, it becomes difficult to compete with a non-collision node, and transmission can be performed with priority.

In this way, immediately after the completion of normal transmission of the message, the transmission waiting time T1 is set as a value of T10min to T10max according to the transmission line usage rate, and the priority of the node is changed. Thereafter, the maximum value of the transmission waiting time T1 is decreased and saturated with time. When a sufficient amount of time has elapsed since the start of message transmission, for example, the transmission waiting time T1 of the node after 10 [s] has elapsed is reduced to between T1fmin and T1fmax according to the transmission path usage rate. For example, it is possible to enjoy the merit of obtaining the same effect by doing the following.

  In normal times, T1 = 10-15 [ms], and when the transmission line usage rate is higher than normal, T1 = 10-20 [ms], and when the transmission line usage rate is lower than normal, , T1 = 1 to 10 [ms], and T1 = 1 to 10 [ms] at the time of collision. That is, when the non-transmission time exceeds a predetermined value, the maximum value of the transmission waiting time is set as a constant value.

  FIG. 5 is a sequence diagram showing a communication example at the time of transmitting a message in the present embodiment.

  As in FIG. 3, while the node N1 is transmitting the telegram 55, the nodes N2 to N4 are transmission factors, and in the first competition, the node N4 transmits the telegram 56, and in the second competition, the node N2 transmits the telegram 57. . This is a condition in which the node N1 again causes a transmission factor during transmission of the electronic message 57.

  Here, when the node N1 and the node N3 compete for transmission right after the transmission of the message 57 by the node N2, the non-transmission time is long for the node N3, that is, the time from the vertical axis to the end of the message 57 is long. Therefore, according to FIG. 4, the maximum value of the transmission waiting time T1 is a low value, and the set transmission waiting time 112 is shortened. On the other hand, since the time elapsed from the completion of normal transmission at the node N1 is short, the maximum value of the transmission waiting time T1 is high and the set transmission waiting time 111 is long according to FIG. Here, the node N3 acquires the transmission right and transmits the telegram 58.

  In this way, by changing the maximum value of the transmission waiting time T1 according to the non-transmission time, it becomes possible to give a transmission right preferentially to a node that is delayed in transmission.

  As described above, priority is given to a node that is delayed in transmission by performing transmission with an appropriate priority for each node by changing the maximum value of the transmission waiting time T1 according to the transmission line usage rate and the non-transmission time. Since the transmission right is given to, prompt transmission is possible.

  However, a node that always obtains the highest priority transmission right may be provided for some special circumstances. For example, if the highest priority transmission right is always given to the centralized control device 4, the user's command as a whole of the air conditioning system is prioritized. This is effective when you want to manage the amount of power in a building.

  Alternatively, if at least one node sets the transmission right as in this embodiment, the priority of the node increases. If this node is, for example, the centralized control device 4, it is possible to perform management in accordance with the above.

  If all nodes connected to this system have the transmission right set as in this embodiment, more nodes can be connected while keeping the congestion level of the air conditioning system at the same level as before.

DESCRIPTION OF SYMBOLS 1 Transmission line 4 Centralized control equipment 21-24 Outdoor units 31-3n Indoor units 51-58 Message 61-63 Transmission waiting time (conventional system, 1st transmission)
71 to 72 Transmission waiting time (conventional method, second transmission)
81-82 Transmission waiting time (conventional method, third transmission)
91-93 Transmission waiting time (this example, first transmission)
101-102 Transmission waiting time (this example, second transmission)
111-112 Transmission waiting time (this example, the third transmission)

Claims (6)

In a communication method of an air conditioning system in which an outdoor unit, an indoor unit, and a central control device of a plurality of refrigerant systems are connected as a node through a single transmission line, and each node is controlled by performing communication.
In order for at least one node to send messages preferentially,
The node is
Measure the non-transmission time, which is the time after the normal transmission of the message is completed,
A communication method of an air conditioning system in which the maximum value of the transmission waiting time is set shorter as the non-transmission time becomes longer. In a communication method of an air conditioning system in which an outdoor unit, an indoor unit, and a central control device of a plurality of refrigerant systems are connected as a node through a single transmission line, and each node is controlled by performing communication.
So that all nodes connected to the transmission line can preferentially send messages.
The node is
Measure the non-transmission time, which is the time after the normal transmission of the message is completed,
A communication method of an air conditioning system in which the maximum value of the transmission waiting time is set shorter as the non-transmission time becomes longer. In claim 1 or 2,
A communication method for an air conditioning system, wherein the maximum value of the transmission waiting time is set to a value corresponding to the degree of congestion of the transmission line. In claim 1 or 2,
A communication method for an air conditioning system, wherein a maximum value of a transmission waiting time is set as a constant value when the non-transmission time becomes a predetermined value or more. In claim 1 or 2,
The communication method of the air conditioning system, wherein the congestion degree is a time when there is a hearing on the transmission line per unit time. In claim 1,
The communication method of the air conditioning system, wherein the at least one node is the central control device.

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