Communication control device

Details Communication control device Communication control device

1998-06-09

2001-04-17

Horabik, Michael (Department: 2735)

Communications: electrical

Continuously variable indicating

With meter reading

C123S429000, C375S371000, C701S102000

Reexamination Certificate

active

06218954

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a communication control device having a transmitting section for serially transmitting two or more input signals, e.g., parallel input control signals, to a controlled section.
2. Description of the Related Art
Various communication control devices are known which allow for communication between units over a communication line. The known communication control devices have more or less the functions as illustrated in block diagram in
FIG. 10
hereof.
The illustrated communication control device
100
comprises a controlling section
110
, a transmitting section
120
, a serial transmission line
130
, a receiving section
140
, and a controlled section
150
.
Based on various inputs, the controlling section
110
supplies a plurality of control signals to a plurality of output ports (0 to N) for controlling the action of the controlled section
150
. The control signals supplied to the output ports contain information for controlling a plurality of controlled objects not shown but provided in the controlled section
150
.
More specifically, the controlling section
110
outputs, for example, to a first output port a signal instructing a first one of the controlled objects to perform an ON/OFF operation, to a second output port a signal instructing a second one of the controlled objects to perform an ON/OFF operation, to third and fourth output ports signals instructing a third one of the controlled objects to hold four different kinds of operational conditions, and to other output ports values for controlling other controlled objects.
The transmitting section
120
constantly monitors the state of the control signals output from the output ports of the controlling section
110
. When a change whatsoever arises in an output state of any one of the output ports, the transmitting section
120
latches the outputs from all of the output ports, parallel-serial converts the latched outputs (into serial bit signals) and supplies the converted signals to the serial transmission line
130
at a preset data transmission speed.
When a change arises in an output state of any output port during an idle state (communication standby state) in which the transmitting section
120
is sending out no serial signals, the transmitting section
120
immediately latches the state of the output port and sends out serial signals.
When a change arises in an output state of any output port while the transmitting section
120
is sending out serial signals, the transmitting section
120
latches the state of the output port and sends out serial signals after transmission of the serial signals being sent out is finished.
The receiving section
140
receives the serially transmitted states of all of the output ports and transmits control signals, resulted from serial-parallel conversion of the received states, to the controlled section
150
in parallel. The states of the output ports of the controlling section
110
are transferred to the controlled section
150
in this manner.
Based on the control signals supplied from the receiving section
140
, the controlled section
150
controls the operation of the controlled objects therein.
In the communication control device
100
of
FIG. 10
, the state of the output ports of the controlling section
110
can be transmitted to the controlled section
150
over a single transmission line connected therebetween.
However, in the above arrangement in which the state of the output ports of the controlling section
110
is transmitted through serial communication to the controlled section
150
, there arises a delay corresponding to the time T required for at least the serial communication beginning at the time when a control signal is newly output from the controlling section
110
and ending at the time when the new signal is transmitted to the controlled section
150
.
Assume, for example, that the controlling section
110
comprises an electronic control unit (ECU) for the ignition spark control and fuel injection, and that the controlled section
150
comprises an electronic ignition system and a fuel injector. Although the controlling section
110
outputs an ignition control signal in such a manner as to achieve the target ignition timing, the actual ignition occurring at the controlled section
150
is retarded by at least the time T required for the serial communication of the ignition control signal between the controlling section
110
and the controlled section
150
.
Thus, the conventional communication control device
100
is arranged so that it outputs control signals intolerable of a delay of the time required for the serial communication, earlier than the target ignition timing (point) set at the controlling section
110
by the time required for the serial communication of the control signals.
Reference is now made to
FIG. 11
which illustrates the operation of the conventional communication control device.
Based on input signals from, e.g., a crankshaft position sensor (not shown), the controlling section
110
calculates a rotational speed and angle of a crankshaft as well as a target ignition timing. As shown in (a) of
FIG. 11
, the controlling section
110
outputs to a predetermined output port an ignition control signal earlier by the time T required for the serial communication than the target ignition point (delay correction).
When it detects a change from a low level to a high level of an ignition control signal as shown in (a) of
FIG. 11
, the transmitting section
120
latches the output states of all of the output ports and serially transmits the latched state of each output port. Since the data length and data transmission rate is preset, the communication time T shown in (b) of
FIG. 11
is constant.
The receiving section
140
receives a series of data sent out from the transmitting section
120
, serial-parallel converts the serial signals and outputs the converted signals.
Consequently, after a lapse of the communication time T from the time of output of an ignition control signal by the controlling section
110
, an ignition output corresponding to the ignition control signal is supplied from the receiving section
140
to the controlled section
150
, as shown in (c) of
FIG. 11
, thereby effecting the ignition spark at the target ignition point.
Reference is next made to
FIG. 12
which is a time chart for explaining the problems of the conventional communication control device.
With the time T required for the serial communication taken into consideration, the controlling section
110
outputs an ignition control signal the time T earlier than the target ignition point (timing). When, prior to the time of output of an ignition control signal as shown in (a) of
FIG. 12
, a separate or another control signal is output as shown in (b) of
FIG. 12
(when there arises a change in the state of an output port), the transmitting section
120
detects a change in the state of the separate control signal and commences serial communication.
Thus, although a control instruction for initiating the feeding of an ignition control signal is output during the serial communication based on a change in the separate control signal, transmission of the state of a new output port including the ignition control signal may not be started until after the previous serial communication is finished (see (c) of FIG.
12
).
Consequently, the actual ignition at the controlled section
150
with an ignition output supplied thereto will be delayed with respect to the target ignition point (timing). The maximum value of the time of delay from the target ignition point is equal to the communication time T required for the serial communication.
As is apparent from the foregoing discussion, in the conventional communication control device
100
, there will be a delay of at most the communication time T before the state of a new output port of the controlling section
110
is transmitted to the controlled section
150
. In other words, the time lag from the output of a control sig

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