DE2029312C3 - Arrangement for the operational activation of step-by-step, pilot-controlled level regulators for carrier frequency systems - Google Patents

Description

The invention relates to an arrangement for the operationally favorable Switching on of step-wise, pilot-controlled level regulators for carrier frequency systems.

As is known, the received, amplified and rectified pilot voltage is used in such level regulators checked by a level discriminator that responds when an under or over level occurs and by means of the impulses of a clock generator the heating current of an indirectly heated thermistor actuator The electronic graduation device advances in the required direction The setting device contains, for example, a binary counter composed of a number of bistable flip-flops (German patent specification 11 18 831).

In the case of regulated amplifiers for carrier frequency systems, it is common practice to assign The gain and the variable resistor are to be selected so that the gain increases as the variable resistor decreases grows

So that the controller retains its position in the event of a pilot failure, a strong pilot drop or a strong pilot increase maintains, it is known to turn the level discriminator around to expand an alarm circuit which, if the pilot voltage deviates from the setpoint at the output of the regulated amplifier by a certain value, e.g. B. ± 0.4 N (alarm level limits), gives an alarm and locks the controller (German patent specification 11 35 524).

The pilot controller has a control range that defines is due to the controller's ability to provide an input pilot level at the output that is within the control range to bring to the setpoint. Is the entrance pi-

3 4

plumb level outside the control range, so he needs to set pilot voltage to the middle position, even in

Not being regulated by the controller, in another case the risk of self-blocking

It is often the case that the distance between the alarm level is present, namely when the controller is without

The setpoint is less than half the control range, the pilot is switched to the central position

If the output level sets outside the alarm level 5 and the returning pilot has a level,

limits, the controller is locked, even if the outside of the alarm limits and within the

the input level is within the control range

These disadvantages are in an arrangement for

This behavior of the controller, which is desirable in itself, is used to switch on step-by-step, pilot-

to the disadvantage when the controller is switched on. io controlled level regulators for carrier frequency systems,

If no special measures are taken, the pilot voltage from a level discriminator

the binary counter of the setting device can be checked, which when an under- or

Take a position that responds to a very low amplification level and the heating current of a

Since the thermistor is only heated indirectly heated adjustable thermistor

must be, the output level always builds from 15 niche adjustment device with one of a number

very small values. If the setting device of bistable flip-flops existing binary counter in the

the thermistor supplies a very small heating current, progresses required direction, and in which the

it can happen that the output level below the level discriminator contains an alarm circuit which at

The lower alarm limit remains even if the input deviation of the pilot voltage from the setpoint by one

level is within the control range The then 20 certain alarm amount (e.g. ± 0.4 N) alarm gives and

Occurring locking and self-locking of the controller locks the controller according to the invention? · -? thereby avoided

However, when the controller is put into operation, the controller must switch the

wants operating voltage by means of a delay circuit

It is known (German patent specification 12 42 706) that it is automatically put into operation according to a program Controller after switching on the operating voltage 25 is so that initially for a short time the to be put into operation automatically according to a program. Adjustment device preset to the central position in such a way that the setting is first made for a short time until the gain is definitely the lower direction to the upper end position of maximum amplification has exceeded the alarm level limit and that subsequently associated line amplifier preset ßend the setting device a certain number is that after reaching the target level or the 30 correction steps into the one when switching on Alarm level (e.g. -0.4 N) due to the pilot voltage level deviation in the opposite direction tion the presetting of the setting device to the power with this number of correction steps one upper end position is canceled and then the gain change corresponds to the slightly greater than Controller automatically assumes its desired position and that the difference between half the control range and the if the pilot voltage is missing or if 35 is not reached, the alarm level distance is and where during the of the lower alarm level (e.g. -0.4N) through the entire switch-on process, the alarm circuit of Pilot voltage after a certain period of time the delay circuit is prevented from functioning position to the upper end position is canceled and that is.

Adjustment device approximately to its middle position. By pre-setting the adjustment device up

is preset. 40 the middle layer, the thermistor is first accelerated

At first, the thermistor is still cold and high-resistance, heated so that the temperature can be reached quickly

the gain and the output level are small, and setpoint is guaranteed.

The controller is blocked After a certain time, the correction steps at the end of the switch-on process NTC thermistor heated up so far that the pilot level has its total ensure that when you switch on with the missing Can reach setpoint. The regulator starts immediately with 45 or very large pilot voltage the regulator does not the reduction of the actuating current until the NTC thermistor is blocked. If the resistance assumes its correct value the input pilot level returns to the control range,

If the pilot voltage is equal to the operating voltage, the controller can correct the residual error.

has also failed, and the operating voltage returns.

if there is no pilot again, it makes sense to change the correction steps so that the gain is reversed

Bring the adjustment device to its central position, because a little more than the difference of half the control range

the probability is greatest that the and the alarm level distance below their mean value.

The target position of the adjustment device is in the middle if the input level is When preset to the middle position, the maximum time is then the upper limit of the control range

possible errors smallest. 55 below causes the existing gain,

The known arrangement (German patent specification that the output level, even if the setpoint only at

12 42 706) can be used for controllers that only achieve the lowest amplification, the upper alarm level

Alert level drop. In the case of a controller that falls below both the gel limit and the controller the residual error

corrects for positive as well as negative level deviations

this is alarmed by a certain alarm value

This arrangement is not applicable if, at a certain pilot level, the gain is at a value which is equal to Input levels that differ little from the mean value in the upper end position Gain adjusted controller one the upper practically the probability of the smallest error Guaranteed to generate output level exceeding the alarm limit

gen and the controller would block itself. 65 An embodiment of the arrangement according to

In addition, for controllers where the distance of the invention shows the drawing, Alarm level from the setpoint level is less than half the PR , the pilot regulator, the setting device, the The control range is and is contained when switching on without a level discriminator and the alarm circuit. VE

is the preset input of the setting device, via which the binary counter is brought to the middle position by applying a negative potential. BE is the blocking input via which the controller is held in its current position by applying a positive potential. AA is the output of the alarm circuit, via which the blocking transistor 7194 is made conductive by applying a positive potential and blocked by removing this positive potential. UB denotes the operating voltage.

During normal operation in the switched-on state, the alarm circuit supplies a positive potential at output AA , and the blocking transistor Ts 4 is conductive. A negative potential is applied to the blocking input BE via its collector, and the controller is not blocked. As soon as the alarm circuit responds and the positive potential at output AA disappears, the blocking transistor Ts 4 is blocked. A positive potential is applied to the blocking input BE via its collector resistor / 7 7 and the controller is blocked.

The switch-on process takes place in two time intervals. In the first time interval, the setting device is held in its central position. The correction steps are carried out in the second time interval. These two time intervals are determined by two separate parts of a delay circuit. The first part of the delay circuit includes a capacitor CI, resistors R 1, R 2 and A3 and transistors TsI and Ts 2. The second part of the delay circuit includes a capacitor C2, a diode Dl, a Zener diode D 2, a transistor Ts 3 and resistors R4, R 5 and R 6.

The switch-on process is as follows:

Across the capacitor Cl is discharged in the off state of the regulator via the discharge resistor R 1 _1, a current flows into the base of acting as a current amplifier Vortransistors Ts 1, the emitter current to flow through its emitter resistor R 2 in the base of the preset transistor Ts 2 and this For the charging time of the capacitor Cl conductive hall Within this first time interval the binary counter receives a negative potential at the preset input VE via the conductive preset transistor Ts 2, and it is held in the middle position. The thermistor of the controller is heated up and the gain exceeds the alarm level limit. Within this time interval, the charging capacitor C2 is short-circuited via the diode D1 and the presetting transistor Ts 2, the transistor Ts 3 receives no base current via di (Zener diode D ' arranged in its base lead and is blocked.

At the end of the first time interval, the transistor Ts2 and the diode Dl are blocked; The capacitor C2 is charged through the resistor A4 si until the breakdown voltage of the Zener diode D 2 is reached. The transistor Ts 3 remains blocked within this second time interval. Over its collector resistance RS and the base resistance / 76 receives the blocking transistor Ts 4 base current regardless of the state of the alarm circuit. The blocking transistor is thus conductive, and the controller is unblocked regardless of the pilot level prevailing. During the second time interval, the setting device is moved in the direction opposite to the prevailing level deviation and makes correction steps.

At the end of the second time interval, the Zener diode D 2 becomes conductive, the transistor TS 3 receives base current and also becomes conductive, and no base current flows into the blocking transistor Ts 4 via the resistor R 6 the blocking transistor is kept conductive via the output AA and the controller can correct the residual error. If at the end of the second time interval the pilot level is outside the alarm level limits, the blocking transistor is blocked and the controller blocked.

1 sheet of drawings

Claims (5)

Patent claims: 1. Arrangement for the operationally favorable switching on of step-wise, pilot-controlled level regulators for carrier frequency systems, in which the pilot voltage is checked by a level discriminator that responds when an under- or over-level occurs and an electronic setting device that sets the heating current of an indirectly heated adjustable hot conductor with one of a number of bistable devices Flip-flops advances existing binary counter in the required direction, and in which the level discriminator contains an alarm circuit which, if the pilot voltage deviates from the setpoint value by a certain alarm amount (e.g. ± 0.4 N), issues an alarm and locks the controller, characterized in that that the controller (PR) is automatically put into operation after switching on the operating voltage (UB) by means of a delay circuit according to a program, in such a way that initially the setting device is preset to the central position for a short time until the gain is certain di e has exceeded the lower alarm level limit, and that the setting device then makes a certain number of correction steps in the direction opposite to the level deviation prevailing when switching on, this number of correction steps corresponding to a gain change that is slightly greater than the difference between half the control range and the alj-megel distance , and wherein the alarm circuit is prevented from functioning by the delay circuit during the entire switching process. 2. Arrangement according to claim 1, wherein the pilot controller, which contains the setting device with binary counter, level discriminator and alarm circuit, a blocking input via which the binary counter is held in its current position by applying positive potential, and has an alarm output at which negative in the event of an alarm and if there is no alarm there is a positive potential, characterized in that a blocking transistor (Ts 4) is provided, the base of which connects to the alarm output (AA) of the controller (PR), the emitter of which connects to the negative pole of the operating voltage (-UB) and whose collector connects a collector resistor (Rl) is connected to the positive pole of the operating voltage (+ UB) and directly to the blocking input (BE) of the controller, the blocking transistor (TS 4) being conductive when there is no alarm and blocked when there is an alarm 3. Arrangement according to claim 1, characterized in that the delay circuit consists of two Parts consists of which one part is the first time interval of the switch-on process, within which the adjuster is preset to the center setting and the second part the second Time interval of the switch-on process within which the correction steps are carried out, certainly 4. Arrangement according to claim 1, 2 or 3, wherein the controller has a preset input via which the binary counter is brought to the middle position by applying negative potential, characterized in that the first part of the delay circuit consists of a capacitor (Ci), a And a Voreinstelltransistor (Ts 2) consists discharge resistor (R I), a acting as a current amplifier prior transistor (TST) having an emitter resistor (R 2) having a collector resistor (R 3), after switching via the capacitor (Ci), which in switched off state of the controller is discharged via the discharge resistor (R 1), a current flows into the base of the pre-transistor acting as a current amplifier (Ts i) , the emitter current of which flows through its emitter resistor (R 2) into the base of the presetting transistor (Ts 2) and keeps this conductive for the charging time of the capacitor (Ci) , and the collector of the presetting transistor (Ts 2) is connected to the presetting terminal (VE) of the controller 5. Arrangement according to one of claims 1 to 4, characterized in that the second part of the delay circuit consists of a diode (D i \ a Zener diode (D 2), a charging capacitor (C2), a transistor (Ts 3) and resistors (R 4, RS, R6) , with the charging capacitor (C2) being short-circuited via the diode (D i) and the presetting transistor (Ts 2) within the first time interval and the diode (D 1) being blocked at the end of the first time interval Charging capacitor (C2) charges itself during the second time interval via the resistor (R 4) as long as the breakdown voltage of the Zener diode (D 2) is reached, and the transistor (Ts 3), which is blocked within the first and the second time interval, is conductive and its collector is connected to the base of the blocking transistor (Ts 4) via a resistor (R 6)