JPS632881Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a backup device for a process control device.

[Conventional technology]

A back-up device is combined with a process control device to take over control in the event of a breakdown or maintenance. In such a case, it is necessary to be able to switch from a normal control state to a back-up control state and to return from the back-up control state to the normal control state without causing any disturbance to the controlled object (bumpless).

Conventionally, the output signal of the control device and the output signal of the backup device were measured separately, and when switching from normal control to backup control, the output signal of the backup device was adjusted to the output signal of the control device, and the output signal of the backup device was measured.・When returning from the up state to the normal control state, back up the output signal of the control device.
I try to match it with the output signal of the booster.

[Problem that the invention attempts to solve]

However, when switching from normal control to back-up control, the output signal may become abnormal due to a failure of the control device, so the output signal of the back-up device may be changed to the output signal of the control device at any time. There is a problem with matching. In addition, some process controllers that are operated by the output signal from the control device do not follow the abnormal change in the output signal from the control device and freeze (lock) the current operating state. Therefore, it is meaningless to give such a process controller the same signal as the control device's abnormal output signal during backup.

In addition, an indicator for measuring the output of the control device, an indicator for measuring the output of the back-up device, and an indicator for indicating the output of the process operating device are provided, and based on these indicated values, the back-up There was one in which the output of the device was matched to the appropriate one of the output of the control device and the process operator. However, this method has the problem of increasing the number of indicators and complicating the circuit configuration.

The present invention was devised to solve the above-mentioned problems, and an object of the present invention is to provide a backup device that has a simple configuration and can respond to any abnormalities in the control device.

[Means for solving problems]

The present invention has a first operation mode changeover switch having four switching states, in which contact 1 is insulated; A pair of second operation mode changeover switches whose contacts change in conjunction with the first operation mode changeover switch are provided, each having two switching states, and an indicator connected between the switching contacts. a first indicated value changeover switch; and a second indicated value changeover switch, each of which has two contacts, the changeover contact being connected to contact 1 of the first indicated value changeover switch. , a DC power source whose positive side is connected to the changeover contact of the first operation mode changeover switch and whose negative side is connected to the contact 4 of the second operation mode changeover switch, and whose anode is connected to the first operation mode changeover switch via a resistor. a zener diode connected to contact 2 of the switch and having both ends connected to contact 2 of the pair of first indicated value changeover switches; and contact 4 of the first operation mode changeover switch and the first indicated value changeover switch. an output signal generation circuit that is connected between contacts 1 of the switch and generates an adjustable back-up output; and a transistor whose collector is connected to the cathode of the Zener diode and whose emitter is connected to the negative side of the DC power supply. , a first diode having an anode and a cathode respectively connected to contacts 4 and 3 of the first operating mode changeover switch; an anode having an anode connected to the base of the transistor and a cathode connected to contact 3 of the first operation mode changeover switch, respectively; a second diode connected to the transistor; a third diode having an anode connected to the base of the transistor and a cathode connected to contact 2 of the first operation mode changeover switch; and a third diode connected to the negative side of the DC power supply and the second operation. a process operating device, the operation amount measurement signal line being connected between contacts 1 of the mode changeover switch and transmitting the measurement output being connected to the contact 1 of the second indicated value changeover switch; A current source is connected to contact 1 of the indicated value changeover switch and whose output can be changed using the hold value operation key, and the anode is connected to contact 1 of the second operation mode changeover switch, and the cathode is connected to contact 2 of the indicated value changeover switch. This is a back-up device for a process control device, comprising: a fourth diode, and a fifth diode, both ends of which are connected to contact 2 of a second indicated value changeover switch.

〔Example〕

The present invention will be explained below with reference to the drawings. FIG. 1 is a conceptual diagram of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a hand/auto circuit forming the output stage of the control device. This circuit is automatic control (auto)
At times, it outputs the control signal given from the previous stage arithmetic circuit (not shown), and during manual control (hand), it outputs the value held in the internal capacitor. The current value of the automatic control signal is held in the internal capacitor when switching from auto to hand, and this held value is automatically adjusted during hand. The output signal of the hand/auto circuit 1 is given to a process operator 2.

3 is a backup device. The backup device 3 incorporates a manually adjustable output signal generation circuit. The backup device 3 is connected to the hand/auto circuit 1 by a connector or the like. Through this connection, between the back-up device 3 and the hand/auto circuit 1, the output signal of the hand/auto circuit 1, the operation amount measurement signal of the process controller 2, and the output of the back-up device 3 are transmitted. Transmission paths for signals and commands to increase/decrease the held value of the hand/auto circuit are formed, respectively. As a result, the output signal of the hand/auto circuit 1, the operation amount measurement signal of the process controller 2, and the output signal of the back-up device 3 are displayed by the indicators installed in the back-up device 3, respectively. . Note that the output signal of the backup device 3 is not applied to the process controller 2 until the operation mode of the backup device 3 is switched to "backup".

In a device configured in this way, back
The application is performed as follows. back up
Prior to switching to the mode, the output signal of the backup device 3 is adjusted to either the output signal of the hand/auto circuit 1 or the operation amount measurement signal of the process operator 2. Which one to use depends on the situation. The clues for determining the situation are the output signal of the hand/auto circuit 1 and the process controller 2.
The difference between the operation amount measurement signals and the presence or absence of an alarm from the controller 2 are as follows. If the two substantially match, it means that process control is being performed according to the output of the hand/auto circuit 1, so the output signal of the backup device 3 is matched to the output signal of the hand/auto circuit 1. On the other hand, if the two values are far apart, the process operating device 2 is locked due to an abnormality in the output signal of the hand/auto circuit 1, or there is an abnormality in the operation amount measurement signal line, so there is no back-up. The output signal of the device 3 is adjusted to either the output signal of the hand/auto circuit 1 or the operation amount measurement signal of the process operating device 2, whichever is normal. Thereby, the output signal of the backup device 3 can be set to a value suitable for the current state of the process controller, whether the control device is normal or abnormal.

Therefore, when the backup device 3 is placed in the backup mode, the signal system becomes as shown in FIG. 2, and the output signal of the backup device 3 is supplied to the process controller 2. Back
Since the output signal of the up-up device 3 is matched with the output signal of the hand/auto circuit 1 or the operation amount measurement signal of the process operating device 2 through the above-mentioned adjustment, switching is performed bumplessly. The process is then controlled by manually adjusting the output signal of the backup device.

When returning from the backup mode to the normal control mode after repair or maintenance of the control device is completed, the output signal of the hand/auto circuit 1 is adjusted to the output signal of the backup device 3 prior to returning from the backup mode to the normal control mode. Adjustment of the output signal at this time is performed by operating keys on the backup device 3 to give commands to increase/decrease the held value to the hand/auto circuit 1. After the outputs match, the return from the backup mode to the normal control mode is performed bumplessly.

The detailed configuration of the backup device 3 is explained by hand.
FIG. 3 shows the state of connection to the auto circuit 1 and the process controller 2. In Figure 3,
301 is a DC power supply, 302 is an output signal generation circuit,
303 is a resistor, 304 is an indicator, 305 is a zener diode, 306, 306' are interlocked operation mode changeover switches, 307, 307' and 308, 308' are indicated value changeover switches, 3
09 is a held value operation key, and 310 is a diode. A diode 101 is also provided in the hand/auto circuit 1. In the normal control mode, the output current of the hand/auto circuit 1 is applied to the process operator 2 through the diode 101.

Lead wires are drawn out from both ends of the diode 101 and the return wire of the hand/auto circuit output current, respectively, and connected to the backup device 3 through a connector. The held value operation command line of the hand/auto circuit 1 and the operation amount measurement signal line of the process operator 2 are also connected to the backup device 3 through connectors, respectively. The diode 310 in the backup device 3 is connected to the changeover switch 306'.
When the contacts 1, 2, and 3 are closed, it is connected in parallel to the diode 101, and when the contact 4 is closed, it is connected in parallel to the series circuit of the diode 101 and the process controller 2. Therefore, at this time, the output current of the hand/auto circuit 1 does not flow to the process operator 2, but is bypassed.

The current of the DC power supply 301 is changed by the changeover switch 30.
Depending on the closed state of the contact 6,306', the flow follows the following path. When contact 1 is closed, it is in a cutoff state. When contact 2 is connected,
A parallel circuit of a resistor 303, a zener diode 305 and an indicator 304, and a changeover switch 30
6'. Here, since the internal resistance of the indicator 304 is small, the current is virtually all transferred to the indicator 304.
Flows through 4. Therefore, the indicator 304 at this time
The voltage of the DC power supply 301 can be checked according to the instruction. When the changeover switches 306 and 306' are turned on to the contact 3, the current of the DC power supply 301 is transferred to the output signal generation circuit 302 and the Zener diode 3.
05 and the indicator 304, and the changeover switch 306'. Since the output signal generating circuit 302 is an adjustable constant current circuit, a current determined by the adjustable constant current circuit is generated. Since the value of this current is indicated by the indicator 304, the output signal of the output signal generation circuit 302, that is, the backup output, can be adjusted while observing the instruction.
When the changeover switches 306 and 306' are turned on to the contact 4, the current of the DC power supply 301 is passed through the output signal generation circuit 302, the parallel circuit of the Zener diode 305 and the indicator 304, the process controller 2, and the changeover switch 306'. flows. This provides a backup output to the process operator 2. At this time, the output current of the hand/auto circuit 1 flows through the diode 310 and the changeover switch 306', but does not flow to the process controller 2.

By switching the indicator value changeover switches 307 and 307', the indicator 304 can be changed to the diode 31.
0 in parallel. diode 3
10, the changeover switch 306' has contacts 1, 2, and 3.
When the contact 4 is connected, it is connected in parallel to the diode 101, and when the contact 4 is connected, it is connected in parallel to the series circuit of the diode 101 and the process controller 2. Therefore, when the indicator 304 having a small internal resistance is connected in parallel to the diode 310, the output current of the hand/auto circuit 1 flows to the indicator 304 at any time, so that the value of the current can be read. In this state, by further switching the indicated value changeover switches 308 and 308', the indicator 304 can be connected to the operation amount measurement signal line of the process controller 2, thereby changing the operation amount measurement signal of the process controller 2. Can be read.

That is, by switching the changeover switches 307, 307' and 308, 308', the indicator 3
04 can display any of the output current of the backup device 3, the output current of the hand/auto circuit 1, and the operation amount measurement signal of the process operating device 2. Therefore, by comparing the output current of the backup device 3 with the output current of the hand/auto circuit 1 or the output current of the process controller 2, it is possible to adjust to either of them.

Another form of the backup device 3 is shown in FIG. In FIG. 4, the same parts as in FIG. 3 are given the same symbols. The device in Figure 4 is a DC power source with 3
01 common line, hand/auto circuit 1
This line is made to be the same as the common line. As a result, the backup device 3 and the hand/auto circuit 1 can be operated using a common DC power source. Changeover switch 306, 306'
and indicated value changeover switches 307, 307',
The transition of the operating mode due to switching of 308 and 308' is the same as in the case of FIG.

Still another form of the backup device 3
As shown in the figure. In FIG. 5, the same parts as in FIG. 3 are given the same symbols. The device of FIG. 5 further includes diodes 311-314 and a transistor switch 315. This device is also designed so that both common lines are common. The transistor switch 315 is in the on state while the changeover switch 306 is closed to contacts 2 and 3, and the zener diode 30
Connect the cathode of 5 to the negative side of the DC power supply 301,
When contact 4 is closed, it is turned off. Therefore, the device shown in FIG.
06' and indicated value changeover switches 307, 30
By switching 7', 308, and 308', the same operation mode transition as in the case of FIG. 3 is performed.

〔effect〕

According to the present invention, the indicator 304 is selectively connected to the output signal generating circuit 302, the diode 101 and the process operator 2 by changing over the switch, so that it is possible to use one indicator to match the output of the backup device 3 to either the output signal of the hand/auto circuit 1 or the operation quantity measuring signal of the process operator 2 as appropriate. This allows the hand/auto circuit 1 to be configured simply.
The effect is that any abnormality in the auto circuit 1 and the process operation device 2 can be dealt with.

[Brief explanation of the drawing]

Fig. 1 is a conceptual configuration diagram of an embodiment of the present invention, Fig. 2 is an operating state diagram of the device shown in Fig. 1, and Figs. 3, 4, and 5 are electrical connection diagrams of an embodiment of the present invention. be. 306...first operation mode changeover switch,
306'...Second operation mode changeover switch,
307, 307'...First indicated value changeover switch, 308, 308'...Second indicated value changeover switch, 312...First diode, 313...
... second diode, 314 ... third diode, 101 ... fourth diode, 310 ... fifth diode.

Claims (1)

[Claims for Utility Model Registration] A first operation mode selector switch which has four switching states, and contact 1 is insulated; and a pair of second operation mode changeover switches whose contacts change in conjunction with the first operation mode changeover switch, each having two switching states, and an indication between the switching contacts. A pair of switches are provided, each having two contacts, and the switching contact is a second indicator connected to contact 1 of the first indicator. an indicated value changeover switch, a DC power supply whose positive side is connected to the changeover contact of the first operation mode changeover switch and whose negative side is connected to the contact 4 of the second operation mode changeover switch, and whose anode is connected to the first operation mode changeover switch through a resistor. a Zener diode connected to contact 2 of the operation mode changeover switch and having both ends connected to contact 2 of the pair of first indication value changeover switches; an output signal generation circuit that is connected between contact 1 of the indicated value changeover switch and generates an adjustable back-up output; a collector is connected to the cathode of the Zener diode, and an emitter is connected to the negative side of the DC power source a first diode having an anode and a cathode respectively connected to contacts 4 and 3 of the first operating mode changeover switch; an anode connected to the base of the transistor and a cathode connected to the first operation mode changeover switch; a second diode connected to each contact 3; a third diode having an anode connected to the base of the transistor and a cathode connected to the contact 2 of the first operation mode changeover switch; and a negative side of the DC power supply. a process controller, which is connected between contacts 1 of the second operation mode changeover switch, and has an operation amount measurement signal line for transmitting the measurement output connected to contact 1 of the second indicated value changeover switch; A power source that is connected to contact 1 of the second indicated value changeover switch and whose output can be changed using the hold value operation key; A back-up device for a process control device, comprising: a fourth diode connected to the switch; and a fifth diode, both ends of which are connected to the contact 2 of the second indicated value changeover switch.