JPS5861233A - Controlling method for temperature of plate - Google Patents

Abstract

PURPOSE:To suppress an abrupt change in the temp. of plates at the changing points of the plates in controlling of the temp. of the plates wherein feed forward (FF) and feedback (FB) are used by fixing the FB control at the changing points of the plates, and correcting the FF control then releasing the FB control after a prescribed time. CONSTITUTION:In the stage of heating strips of respective lots differing in materials, thicknesses, widths, etc. while allowing the strips to travel continously in a treatment under heating for plate materials such as rolled strips, the FB control which changes heating conditions according to deviations in the temp. of the plates is fixed at the changing points of said plate materials. Then the difference in the quantity of heating corresponding to the difference in the information on the plate is applied as a correction for the FF control, and the respective plates are heated under optimum heating conditions in accordance with the information on the plates, the target values for the temp. of the plates, and heat transfer equations. After a prescribed time, the fixing of the FB control is released, and the cntrolling for the temp. of the plates wherein the FF control is used in combination is resumed. Thus the temp. is stabilized at prescribed values quickly without generation of any temp. deviation.

Description

Detailed Description of the Invention The present invention relates to heat treatment of plate materials such as rolled strips, and in particular, the present invention relates to heat treatment of plate materials such as rolled strips, and in particular, the present invention relates to heat treatment of plate materials such as rolled strips. Regarding temperature control.

The temperature of the rolled IJ tube or the like is controlled to a predetermined temperature through a heating furnace, a soaking zone, a cooling zone, etc. Since the strip has recuperated heat, the temperature control cycle of heating, soaking, and cooling is usually repeated, and control is performed so that the strip reaches a predetermined temperature upon exiting this temperature control stage.

Normally, in such temperature control, it is quite difficult to obtain a highly accurate sheet temperature because stubs with different rolling lofts or product materials and dimensions are continuously passed through a heating furnace or the like by welding. Therefore, in the past, as shown in Figure 1, for example, a high-level computer S
Enter board information and required information for temperature control in CC, and press S.
At CC, each time a plate with a different loft arrives, the heating conditions are determined using the required calculation formula including the heat transfer equation, and the parameters of the feedforward control are changed, and the feedforward control parameters are continuously adjusted in response to the outlet side plate temperature, which is the force control result. and change the feedback control parameters. Heating control data is sent to a computer (analog circuit or microprocessor) lower than SCC by FTCI.
Then, the cooling control data is given from the SCC to the lower-level computer FTC2, and these computers FTCI and FTC2 adjust the data according to the heating characteristics and cooling characteristics of the fuel control valve FCV, cooling prower BR, etc., and also the temperature detection of the temperature sensor TSm. Heating according to the characteristics.

Converts cooling data into operation amount and drives the drive circuit FCD.

Give to BCD. The strip driving speed (line speed LS) is calculated by the SCC and given to the motor driver MCD. 1 is a strip. In Figure 1, one furnace section is shown as having a heating burner (FCV system) and a cooling blower BB, but normally a soaking zone is placed downstream of the heating furnace equipped with the heating burner, and then cooling is performed. Blower B
A cooling zone with B is arranged.

Conventional plate temperature control can be summarized as follows.

(1) Heating control (a) Feedforward (FP) control In plate temperature control mode I (speed control), the SCC calculates the furnace temperature and line speed from the heat transfer equation, and sends the furnace temperature to the FTCI and the electric controller MCD. Set the speed at the right time. In the plate temperature control mode (2), the plate temperature is preset in the FTCI at an appropriate timing.

In p T Cl&'i % furnace temperature control, control is performed to reach a target furnace temperature.

The MCD controls the target speed.

(b) Feedback (FB) control In plate temperature control mode I (speed control), the SCC
If the plate temperature deviation exceeds a certain value for 10 seconds (20 seconds), the speed is calculated and the electric controller M
Set to CD.

Board temperature control mode In the river, only board temperature presets are available.

FTCl performs FB control every 0.3 seconds in the furnace temperature control mode.
．． FB control is performed every 39 times.

The MCD controls the speed to reach the target speed.

(2) Cooling control (al feedforward (FF) control) The SCC sets the number of drive fans and the rotation speed to the FTC 2 based on the coil information, learning results, and heat transfer equation (standard cooling capacity).

FTC2 performs fan ON-OFF and rotation speed control.

(b) Feedback (FB) control The SCC collects the actual plate temperature every 108 times, calculates the number of driving fans and the rotation speed, and outputs it to the FTC 2 (pattern determination).

FTC2 performs fan ON-OFF and rotation speed control.

In this type of conventional plate temperature control, the host computer SCC performs tracking for each plate, coil (plate) data setting, F
It shares many tasks such as Ii' setting calculations and FB control calculations, and mainly performs device setting control that executes instructions for lower-order computers FTC1, 24 and 8CC, and upper-level computer S
There are many CC tasks.

In addition, when changing plates, the heating and cooling settings are changed by FF control to values that match the newly arriving plate, but since FB control is continued, the plate temperature changes greatly at the plate changing point, and the plate temperature does not change. Generates transient hunting,
do.

The primary purpose of the present invention is to suppress plate temperature changes at the plate change point, prevent plate temperature hunting, and quickly bring a new plate to a desired temperature, thereby reducing the tasks of the host computer. This is the second purpose.

In order to achieve the above object, in the present invention, the tasks of board tracking, coil data setting, target temperature setting, and FB fixed timing calculation at the time of board change are assigned to the host computer SCC, and the tasks of calculating the FB fixed timing when changing boards are assigned to the lower-order computers FTC1 and PTC2.
Control and FB control are assigned, and FB control is temporarily fixed at a predetermined timing of board change.

In a preferred embodiment of the present invention, SCC is the thickness t of the plate currently under heating control. 1 and the thickness of the next slope t+(if?
), and after the plate change point (welding point ■) moves by XH from a predetermined position, the FB control is fixed at the value at that time. Also SC
C is the target temperature T for the plate thickness.

It has data indicating °C, and this 16 °C is set in the lower computer. Furthermore, SCC is the current plate thickness Lci and the next plate thickness t. It has plate feed speed LS change timing data xv (□) specified by (1+4), and the motor driver (drive circuit) that determines the plate speed after the plate change point (welding point e) has moved by ) Give the changed plate speed L8 data to MCD. Lower level computer (FTCI) is 80
The manipulated variable M is calculated using the manipulated variable calculation model with the plate width W, plate thickness t, and plate speed V given by C as parameters, and P
F preset, and calculate the operation amount that sets the difference between the feedback value of the outlet plate temperature and the target T0 given by the SCC to 0, add it to the preset value, and further calculate the zone distribution to calculate the value for each zone. Set in the manipulated variable controller and stop changing the FB controlled variable based on the SCC command. When changing boards, the difference ΔMFF between the previous preset operation amount and the preset operation amount to be set this time is calculated, and Δ'MFF' is added (including subtraction) to the previous preset operation amount.

According to this, the feedback control amount is stabilized at a value that provides the desired plate temperature immediately before plate change, and this value does not require major changes even if plate thickness, machine width, etc. change. Therefore, even if the feedback (FB) control amount was fixed and the manipulated variable was changed to the feedforward (FF) control amount corresponding to the plate to be heat treated this time, no large temperature deviation occurred and the Ft'' control result was obtained. The temperature deviation at this point in time is small. Therefore, if the FB control is applied at the time when the FF control result appears, the temperature quickly stabilizes to the desired value.

FIG. 2 shows a system configuration for implementing one aspect of the present invention. Temperature control is a heating furnace HF in this example.

1st soaking zone 18. 2nd soaking zone 28. 1st cooling zone IQ 3rd
This is carried out in the soaking zone OA and the second cooling zone 2C. The position calculator SCC uses a professional computer as before, but
A microprocessor 8TC for plate temperature control and a microprocessor FTC for furnace temperature control are used as the lower-level computers (F't"CI, FTC2). 8TC and FTC are C
The RT process console is housed on a PCB and each consists of a plurality of furnaces or zone sections. In addition to the two CRT displays, the CRT process console PCB has
A keyboard is provided for interrupt operations and settings.

Fuel control valves for heating furnaces, soaking zones and cooling zones.

Blower, heater, motor, etc. are driver (drive circuit) SD
A driver SDR is connected to the microprocessor of the PCB via an interface.

There is a board on the inlet side of the heating furnace HF! A plate tracking device that emits one pulse (feed synchronization pulse) for each predetermined length of feed, and a welding point detector WPD that detects the welding point between the plates are arranged, and the feed synchronization pulse and welding point detection A signal is provided to scc.

The data held by the SCC and the arithmetic processing of the 8CC are
Shown in Figure a. Note that the thick black frame sections in FIG. 3a approximately correspond to the furnace and zone sections (FIG. 2).

The SCC stores plate (coil) information in the order in which the plates arrive. As explained below, the manipulated variable M of the FF control is determined by the model formula M:=-kwtv, so the plate information is the plate width W, plate thickness t, and plate speed V. Attached to these are upper and lower cooling rate limits of (see block CDB in FIG. 3a). SCC is W
The welding point detection signal from the PD detects the plate change, and the position of each part of each plate is tracked by counting the feed synchronization pulses from the plate tracking device. Soaking zone 1s, 28. OA, and 1st. Second cooling zone 1c.

Performs 2C heating and cooling control.

FIG. 3b shows a control system for controlling the heating furnace HF.

This control system includes a heating furnace plate temperature control computer (microprocessor) 8 T CHF, which forms part of the plate temperature control STC;
A heating furnace furnace temperature control computer (microprocessor) FTC) which forms a part of the furnace temperature control FTC) is composed of IF and control circuits SDPHFl, 8DPHF2'C.

FIG. 3C shows the configuration of a control system that controls the first soaking zone IS and the second soaking zone 2S. This control system includes soaking zone plate temperature control calculators (microprocessors) 8TC1s and 2s and hysteresis circuits 5TC12sc, which form part of the plate temperature control STC, and heater drino<5DP1s+8DP2s and motor drivers 8DP2 and 2, which form part of the driver SDP. It is configured.

In Figure 3d, 1. The configuration of a control system that controls the second cooling zones IC, 2C and the second soaking zone OA, and controls plate feeding is shown. This control system is a cooling strip plate temperature control computer (microprocessor) that forms part of the plate temperature control 8TC.
TC1°, as well as a control circuit 8 DPtct forming part of the driver 8Dt'.

8DP1c2, 5DPOA1, 8DP2(, 8DP
Consists of HF3.

Hereinafter, plate temperature control in each of the furnace and zone (FIG. 2) will be explained with reference to the block shown in FIG. 3a and the configuration of the control system shown in FIGS. 3b to 3d.

(1) Heating control of heating furnace HF...Block HFB
, ~HFB3 (FIG. 3a) and block HFB in FIG. 3b, the SCC is the plate thickness t of the plate currently being controlled and the plate that will arrive next. FB fixed timing data XH(m) with i, jc(i+1) as parameters
(Distance of welding point from WPD when fixing FB)
When information indicating a board change is given, this data XH is accessed and read out, and S T CT
(Give F the signal S11 indicating that the FB control is fixed, and further give the coil data (W+'e v) to calculate the current fuel supply amount T/1■ (1) and the next T/H (i+n In other words, the current manipulated variable Mi and the next manipulated variable M+1 are S T CH
F is calculated. 5TCHF fixes the set value of FB control in response to Sh1. Furthermore, s'rcHF is Mi and Mi+
+ is compared, and if the difference is greater than a predetermined value, the FF control setting value is changed (determined in step 8e1).

5TCHF responds to this by setting the FF control setting value to Mi +1.
Change ΔM2Mi−Ml+1 minute from the current setting value, and fix the FB control amount. sec is the plate target temperature data S VT (F is S T CHF
Furthermore, the speed timing data xy is accessed using tci and □tc (1+1), and the plate feed speed L8
is calculated and the board feeding speed L8 is set in the motor driver 8DPHFs at the timing of Xy.

Thereafter, the SCC performs S
Instructs CHF to release FB control fixation.

Since the heating furnace HF consists of 7 zones, F T
The CHF distributes the FFFF control setting amount MV output by the 8 T CHF to each zone, and calculates the amount assigned to each zone.
Provided to arithmetic controllers 8DPHF1 and 5DPT (F (7 sets each).Arithmetic controller 8DP
HFl and SDPHF2 each include an error amplifier and a PID control circuit, and control the fuel flow rate to a specified value.

(2) Heating and cooling control of the 1.2 soaking zone...Blocks 188, 28B, 28B2 (Figure 3a) and 3C
figure.

As shown in block ISB, SCC is block HFB
The target furnace temperature 5v1s is accessed from the target temperature T0 accessed in , and is given to the hysteresis comparison circuit 8TC12SC. Circuit 5TC128C has 5VIS and current furnace temperature p
Compared with v, when Sv, S>Pv, a heater energization instruction is given to the heater driver 5DP1S, and -1-s v
1S +a = p v heater driver 5DP1S
By instructing the heater to stop, this α-minute hysteresis prevents repeated O from passing around the Pv of the heater.
N, OFF is prevented. The board changing section is the second soaking zone 2
At a predetermined timing when entering S, the SCC executes block 28
As shown in B, the FB control fixed timing XH is accessed using the current plate thickness tci and the next plate thickness Lc (1+1), and the FF control amount is changed (coil data W #
t; VLS is changed in (1) above), and the timing x1. Instructs STC, S, and 2s to fix the FB control. 8 T 01B + 2 S is 5TCHF
Perform the same FF control settings as above, but do not fix the FF control. This is because it is determined by L8 month IF control. PTC2S, which forms part of the furnace temperature control FTC, is 5
TCIS, converts the operation amount of FF control and FB control given by 2s into heater on/off duty control timing and cooling distribution of blower B to control heater on/off,
and set the speed of blower B. Note that the SCC releases the 1·゛B control fixation after the board temperature corresponding to the board change appears.

(3) Soaking and cooling control of the first cooling zone IC, third soaking zone OA, and second cooling zone 2C...Block ICB.

~' CBs m OA B and 2CB (Figure 33)
And in Fig. 3d, 8TC1C performs FF control corresponding only to the plate thickness t, 8T'
Do the same as C1S and 2S. SCC also independently has FF control and FB control based on a simple model and learning (block ICB). sTc, block of c (TI of 3rd d[
S is the target plate temperature before the start of cooling (the target plate temperature of 28 is TiA
The actual plate 1i1it·Tos indicates the target plate temperature of the cooling layer, and these learning data are added as the second FF control data. The first cooling zone 1c is air-water cooling, and s'
rc1 (3 is cooling to each cooling nozzle (T゛-T
) Distribute (N---□・■). The cooling P@CR operation amount for each nozzle is the control circuit 8DP. 1 and a function generator.It is set by the control circuit 8DP1c2.

S D P2O3 sets and controls the target water drain amount based on LS and the total amount of cooling water.

The SCC directly sets the target temperature to the third soaking zone OA and the second cooling zone 2c. Give V2C. 5vo
A is a comparison circuit 8 having hysteresis characteristics D poA
The furnace temperature PV of the OA is compared with 5voA, and the heater driver S D PoA
2, a heater on/off instruction is given. 2nd cooling zone 2
In C, the number of SCC instruction blowers is □ -
driver 8. DP2C and specified professional)
AB performs 2C cooling.

One embodiment of the present invention has been described above, and in this,
8TCT (F, 5TC2S, and 5TC1c), FB control is fixed when changing plates.According to the present invention, FB control may be fixed with only one of these, but heating furnace HF control (STCHF ), it is most effective to fix the F'B control.

[Brief explanation of the drawing]

FIG. 1 is a simplified block diagram of a conventional plate temperature control system. FIG. 2 is a block diagram showing an overall outline of a plate temperature control system implementing the present invention in one embodiment, and FIG. 3a. FIGS. 3b, 3c, and 3d are block diagrams showing in more detail the system configuration based on FIG. 2, and FIG. 3a shows memory data and control processing of the program controller scc. SC, C: Upper computer (Procontroller) FTCI, FTC2: Lower computer Figure 1

Claims (2)

[Claims] (1) Combining feedforward control that sets the optimal heating conditions for each plate based on plate information, plate temperature target value, and heat transfer equation, and foot control that changes heating conditions according to plate temperature deviation. In plate temperature control, when a plate arrives whose plate information differs from that of the plate currently under heating control, feedback control is fixed at the plate switching point, and the difference in heating amount corresponding to the difference in plate information is fed forward. A plate temperature control method characterized by adding correction to the control and releasing the fixed control after a predetermined period of time. (2) The plate temperature control method according to claim (1), wherein when changing the speed of a board with the same board information, the speed change is set to feedforward control.