Siemens Level 1 actual Exam (Latest 2026/ 2027 Update)
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Question:
How can the piston speed of cylinder 1A be greater during retraction than it is in extension for the control system
shown below?
Answer
*NOT By installation of a quick exhaust valve between valve 1V1 and 1V2*
Question:
Which statement about the operation of the control circuit shown below is correct?
Answer
After pushing S1 cylinder 1A retracts immediately.
Question:
The text below represents the logical association between transition conditions. Which of the transition conditions
represented by Boolean expressions, logic symbols and standardized circuit symbols are correct?
Answer
Solution B, Solution E
Question:
Which of the following displacement step diagrams show the operations of the cylinder 1A and the valve 1V1 correctly
in the pneumatic circuit diagram below?
Answer
Diagram A
Question:
For the pneumatic circuit diagram shown below, which task does valve 1V2 do?
Answer
It serves to set the forward speed of cylinder 1A.
Question:
Which of the following output voltages based on the float position of an automotive fuel level sensor, as shown below,
is correct?
Answer
10V 5V 0V
Question:
An electrical power supply is shown below. Which statements about the functionality ofthe circuit are correct?
Answer
*NOT The diode rectifier changes the AC voltage to a pulsating full-wave DC voltagethat is smoothed by the capacitor
C1. AND If the fuse is blown, the AC voltage between point 2 and 3 will be 230 V.*
Question:
In a testing application inspection cylinder 2A has to distinguish between lower and upper half cubes, as shown below.
Which statements about the mode of operation are correct?
Answer
*NOT In Figure a, the part is recognized as a lower half cube. Inspection cylinder 2A has reached the extended end
position, which is detected by sensor 2B1. AND In Figure b, the part is recognized as an upper half cube. Inspection
cylinder 2A has reached the extended end position, which is detected by sensor 2B1.*
Question:
The result from a "Teach in procedure" of an ultrasonic sensor with analog output is shown below. Which statements
about the operation of the sensor are correct?
Answer
The output voltage when an object is detected at a distance of 55 mm is ˜ 5 V., The voltage at the output alters by 10 V /
50 mm = 0.2 V / mm, starting from the zero point.
Question:
The switching frequency of a power electronic for a DC machine is set to 2 kHz. This could cause:
Answer
Annoying noise.
Question:
Picture A shows an electrical circuit with a motor. Part #3 compares current I1 and I2. If the current I1 is not I2 equal
part #3 breaks the circuit. Which safety function does circuit element #3 accomplish?
Answer
Protects the operator from current flow through the machine housing
Question:
The internals of an automotive gearbox are shown below. What condition must hold true if any two gears of the type
shown are to mesh properly?
Answer
The teeth of both gears must be the same size., The shafts must be parallel
Question:
The builder of the automotive racing engine shown in the picture decided to use socket head cap screws to attach the
valve covers. What is the pitch of the screws used?
Answer
2mm
Question:
Which components are used for energy transport between different machine units of a system?
Answer
Timing Belts, Power Screws
Question:
The Boolean equation for the logic represented in the ladder diagram shown below can be expressed as ...
Answer
Y = (A) + (C ) + (BC)
Question:
The move instruction copies data from ...
Answer
... a source byte to a destination byte.
Question:
The symbol shown below in the ladder diagram ... (looks like --| |--)
Answer
... can be thought of as a contact that is usually opened.
Question:
The maximum number of networks allowed in a Step 7 program is ...
Answer
... limited only by the memory size.
Question:
Which of the following counter is available in STEP 7?
Answer
Up/Down counter
Question:
What is the use of the cushioning of a double-acting cylinder?
Answer
It prevents a hard striking of the piston at the end positions.
Question:
Which statement about a single-acting cylinder is correct?
Answer
The retraction of the piston is usually achieved by a spring.
Question:
Given for the system shown below: A1 = 50 cm2, A2 = 800 cm2, s1 = 16 cm. Determine s2.
Answer
s2=1cm
Question:
The electrical circuit diagram and the pneumatic circuit diagram of a control system are shown below. Which
statements about the mode of action are correct?
Answer
As long as no pushbutton is pressed, the directional control valve remains in the retracted end position. AND The
piston rod of the cylinder is to be advanced if either of the two pushbuttons S1 or S2 is pressed.
Question:
Which statement about detecting the advanced or retracted end position of a piston rod, as shown below, is correct?
Answer
The field of a magnet causes the two reeds to close, allowing current to flow.
Question:
The function diagram and function chart of a pick and place system are shown below. Which statement about the
operation is correct?
Answer
*NOT After the vacuum was switched off in Step 7, the stop cylinder retracts.*
Question:
A swivel arm unit and its corresponding pneumatic circuit diagram are shown below. Which statements about the
operation are correct?
Answer
The swivel arm's rotation cylinder is operated by the 5/3-way double solenoid valve +SWIV-1V1. AND As long as
solenoid +SWIV-Y3 of DCV +SWIV-1V2 is energized, vacuum is switched on.
Question:
Which components in the air supply unit, as shown below, are correctly identified?
Answer
Pressure regulation valve with adjusting knob - A AND Air filter with water separator - C
Question:
In the pick-up and place application, as shown below, the pick-up cylinder 10A1 moves downward at the pick-up
position but the pneumatic gripper 11A1 does not close to grab the part. Which of the following components can be the
cause of the problem?
Answer
*NOT Cylinder position sensor 10B1 AND PLC input module 2*
Question:
A 24 V DC contactor controls a 3-phase AC motor (230V/400V). Which of the following measurements are correct?
Answer
Contactor activated: 400 V between terminal 1 and 4. AND Contactor activated: 400 V between terminals 1 and 6
Question:
Which statements about the installation and adjustment of the synchronous belt drive shown below are correct?
Answer
If both pulleys are properly aligned, all four edges of the pulleys (1, 2, 3, and 4) should be touching the straight edge.
AND If the pulleys are not aligned, the belt will run up against the pulley flanges causing excessive belt wear.
Question:
Which of the following rolling contact bearings are able to absorb thrust forces at least from one side?
Answer
Bearing a, c and d.
Question:
An electrical DC machine gets too hot during operation. What could be the cause?
Answer
There is malfunction in the cooling system. AND The load increased.
Question:
A frequency inverter has a malfunction: one low-side switch is broken and as a result always opens. Result for the
driven asynchronous machine:
Answer
More torque ripple and more noise. AND Less maximum torque.
Question:
A system contains two identical circuits operating in parallel as shown below. As long as both are operating properly,
the outputs of both circuits are always the same. If one of the circuits fails, the outputs will be at opposite levels. To
indicate the failure, the outputs of the circuits are connected to the inputs of ...
Answer
...an XOR gate.
Question:
The basic difference between a PLC and a relay control system is that ...
Answer
... one uses relay control logic and the other uses programmed instructions.
Question:
A device used to convert a binary number to a 7-segment display format is ...
Answer
... a decoder
Question:
Given below is the truth table of a 3-input logic gate. Which logic gate represents the behavior between inputs and
outputs according to the truth table?
Answer
NAND gate
Question:
What is the use of end position cushioning of a double-acting cylinder, as shown below?
Answer
It prevents a hard striking of the piston at the end positions.
Question:
In the control circuit shown below, which action will trigger the extension of cylinder 2A?
Answer
By activating the proximity sensor 1B2.
Question:
In the pneumatic controlled system shown below, the cylinder does not retract. Given the following measurements,
what could be the possible cause of the malfunction?
Answer
Adjustable one-way flow control valve 1V2
Question:
By observing the meters in the electrical circuit shown below, determine the type of failure in the circuit and which
component failed.
Answer
R1 and R2 are shorted.
Question:
Which statements about the mode of operation of the forward/reverse control circuit, as shown below are correct?
Answer
*NOT If S1 is pressed the motor will rotate in the forward direction until S3 or S2 are pressed AND If "STOP" and
"START" are both pressed at the same time nothing will happen.*
Question:
The current error situation of the control circuit, as shown below, is described as follows: The claw is closed, the motor
M1 does not start. Which statement about troubleshooting are correct?
Answer
*NOT If the sensor B1 does not send a 1-signal to the PLC input I1.6, contactor K1 should be checked first. AND If the
input signal I1.6 of the PLC is low, the sensor B1 should be checked.*
Question:
In the feeding application, as shown below, cube halves are pushed out from a magazine. Which statements about the
mode of operation are correct?
Answer
The micro switch checks that cube halves are present in the magazine. AND The fully retracted end position of feed
cylinder 2A1 is detected by sensor 2B2.
Question:
The function diagram and the function chart of a feeding and lifting device are shown below. The pallet lift cylinder 2A
extends, sensor 2B2 is triggered, status indicator of PLC I0.5 is on, the pallet feed cylinder 1A does not extend. What
makes sense to do next to fix the problem?
Answer
*NOT Check the cable between sensor 2B2 and PLC input I0.5. AND Measure the supply voltage of sensor 2B2.*
Question:
The ideal rotating magnetic field in the stator of a three-phase machine is deformed by:
Answer
Non-symmetrical stator windings. AND Non-ideal net situation.
Question:
An image of the internals of an automotive differential are shown below. The pinion gear with 14 teeth is driving the
ring gear with 42 teeth. If the pinion turns at 420 rpm, what will be the speed of the ring gear?
Answer
140 rpm
Question:
Which of the following statements about a NAND gate are correct?
Answer
If all inputs are 0, the output will be 1. AND If one or more inputs are 0, the output will be 1.
Question:
Which of the following input combinations will definitely result in an output?
Answer
C AND D
Question:
The preset number of 86 is entered on the keypad and also appears on the 7-segment display. What is the specified
content of register A and the data on 8-bit input B of the comparator when the carton is full?
Register A: 1000 0110 Comparator input B: 0101 0110
Question:
In programs that are written in ladder logic, all outputs are represented by ...
Answer
... coil symbols.
Question:
Field devices refer to ...
Answer
... all kind of sensors and actuators that are physically wired to PLC input/output modules.
Question:
The electrical circuit diagram and the pneumatic circuit diagram of a control system are shown below. Which
statements about the mode of operation are correct?
Answer
The prerequisite for the return movement is that first pushbutton S1 must have been released. AND When the
advancing piston rod reaches the forward end position, the solenoid coil 1Y2 is actuated via limit switch 1S2 and the
piston rod retracts.
Question:
The force of retraction F (in N) of a double-acting cylinder when retracting should be calculated. In which of the
following formulas is the relationship correct mathematically described?
Answer
*NOT F = 10 pe (pid^2)/4 - d**
Question:
Based on the control settings, find the peak-to-peak amplitude and the period of the waveform displayed on the scope
screen and calculate the frequency.
Answer
*NOT 0.9 V 0.5ms 2.0Khz*
Question:
Which of the following statements about solenoids and relays is correct?
Answer
A solenoid is an electromagnetically controlled device in which the mechanical movement of a plunger is activated by a
magnetizing current.
Question:
The figure below shows a graph of current as a function of voltage for three resistance values. Determine R1, R2, and
R3.
Answer
1.0 kohm(s) 2.2 kohm(s) 4.7 kohm(s)
Question:
An automotive application involves an inductive sensor that detects the crankshaft positionto adjust the fuel control
system. The result of a test measurement at the output of thesensor is shown below. The magnitude and rotational
speed are ...
Answer
*NOT 1.2 V, 12,000 r.p.m.*, POSSIBLY 1.2 V, 3000 r.p.m.
Question:
Which component has to be maintained most often in a small DC machine?
Answer
Brushes
Question:
The PLC program is uploaded from the programming device into the PLC. Into which specific CPU-Memory of the PLC
is the program loaded?
Answer
Load memory
Question:
In PLC operation, a scan is usually a sequential process of ...
Answer
... reading the status of inputs, evaluating control logic, and updating outputs.
Question:
The status bit of switches and pushbuttons connected to a PLC input module are stored in the ...
Answer
... process image input file.
Question:
What kind of signal varies continuously?
Answer
Variable signal (some may say Analog signal though)
Question:
The basic function of a PLC is to ...
Answer
... accept inputs, make logical decisions, and send outputs.
Question:
The basic difference between a PLC and a relay control system is that
Answer
... one uses relay control logic and the other uses programmed instructions.
Question:
The symbol shown below in a ladder diagram represents a(n) ... (looks like --{ }--)
Answer
... imaginary coil that, when energized, will activate a digital output contact.
Determine the number of possible combinations of a six digit binary number.
Answer
64 combinations
The largest decimal number that can be represented with eleven binary bits is ...
Answer
... 2047.
The binary number 1010 0111 1100 0101 can be written in hexadecimal as ...
A7C5
The conversion of the floating point binary number 1011 1101.0110 to decimal is ...
189.375
The conversion of the decimal number 156 to 8421 BCD is...
0001 0101 0110
If a given memory unit consists of 2,400 bytes the memory capacity would be rated:
19,200
Which of the following statements about a NAND gate are correct? Two answers are correct.
If all inputs are 0, the output will be 1. AND If one or more inputs are 0, the output will be 1.
If you want to know when one or both matching bits in two different words are logic '1' you would use the ...
... OR instruction.
A system contains two identical circuits operating in parallel as shown below. As long as both are operating properly,
the outputs of both circuits are always the same. If one of the circuits fails, the outputs will be at opposite levels. To
indicate the failure, the outputs of the circuits are connected to the inputs of ...
...an XOR gate.
The Boolean equation for the logic represented in the ladder diagram shown below can be expressed as ...
Y = (A) + (C ) + (BC)
Branch instructions are used to create:
parallel paths.
By which system does the CPU communicate with input and output modules located on the same rack?
Backplane Bus
The Central Processing Unit (CPU) ...
... accepts inputs, makes decisions provided by the program, and sets outputs.
The maximum number of outputs allowed per network in a Step 7 program is ...
... limited only by the memory size.
Parallel connections of a ladder logic program are typically called ...
... branchs.
.
An 8-bit binary counter has to count balls going into a box from a conveyor belt. A sensor detects the passing of a ball.
If it has counted one hundred balls, the binary value of the counter is ...
... 0110 0100.
Q.
Two pushbuttons and a proximity switch of a PLC controlled mechatronic system are connected to PLC inputs and a
contactor is connected to a PLC output. Which of the following statements according to Network 2 and the program
extract shown below is correct?
K1 is only activated when pushbutton PB2 is pressed and sensor B1 is activated.
The connections of input and output devices to the PLC and the corresponding ladder logic program are shown below.
Which of the following statements about the operation are correct? Two answers are correct.
If pushbutton S1 is pressed and pushbutton S2 is pressed, solenoid 1M1 is energized. AND If neither pushbutton is
pressed, solenoid 1M1 is de-energized.
As shown below, the LED display connected to a PLC output module enables the machine operator to view the number
of workpieces produced. Which of the following statements about the display are correct? Two answers are correct.
The LED display shows the decimal form of the binary coded decimal value (BCD). AND To display the next higher
number, in this case 39, only PLC output QX.0 must be changed to 1.
The Boolean equation for the logic represented by the relay circuit diagram of the drilling machine
shown below can be expressed as:
M : K1 = PB1 x PB2 x B1
At the operator panel you find out that the output of the PLC to execute the next step is set, but this step is not
executed. Which action should you take to find the fault?
Checking the signals between output module and actuator
A sudden increase in the total current, in a parallel circuit, as shown below, may indicate:
A short circuit
In a voltage divider circuit, as shown below, the individual measured voltage drops across resistors R1, R2, and R3 are
greater than the calculated values. What is the possible malfunction?
R4 is shorted
The voltage divider circuit board, as shown below, does not provide the specified voltages: 24 V at pin 3 and pin 4, all
other pins have 0V. The voltages specified with respect to the negative terminal of the power supply are given:Pin 1:
negative terminal of the 24 V power supplyPin 2: 5.4 V ± 5 %Pin 3: positive terminal of the 24 V power supplyPin 4:
20.8 V ± 5 % Pin 5: 16.0 V ± 5 % Pin 6: 14.6 V ± 5 % Pin 7: 2.0 V ± 5 %The circuit does not provide the specified
voltages. Identify the likely fault for the following case: 24 V at pins 3 and 4. All other pins have 0 V.
There is an open circuit between pin 4 and pin 5 (R5 open).
The circuit below shows a basic panel illumination circuit schematic. Which of the following statements about the
functionality of the panel illumination circuit, as shown below, are correct?
The fuse is for circuit protection in case of a short circuit AND The brightness of the lamp is proportional to the
amount of current through the lamp
In the crankshaft position sensor, as shown below, the induced voltage across the coil is caused by ...
... a tab passing through the magnetic field.
When the needle of an analog ohmmeter indicates infinity, the resistor being measured is:
Shorted
110 V AC is applied across the primary winding of a transformer. When you check the voltage across the secondary
winding, you get 0 V. Further investigation shows no primary or secondary currents. The cause of the malfunction is:
The primary winding is open.
A 3.3 kohm resistor has burned out in a circuit. You must replace it with another resistor with the same resistance
value. If the resistor carries 50 mA, what should be its power rating? Assume that you have available resistors in the
following power ratings: ¼ W, ½ W, 1 W, 2 W, 5 W, 10 W, and 20W.
10 W
You are measuring the current in a circuit that is operated by a 24 V DC power supply. The ammeter measures 48 mA.
Later, you notice that the current has dropped to 40 mA. Eliminating the possibility of a resistance change, you
conclude that the voltage has changed. How much has the voltage of the power supply changed?
20V
A Wheatstone bridge is used in a temperature-sensing application. The temperature of a liquid in an industrial process
is monitored using a thermistor in one branch of the bridge, as shown below. From the graph of thermistor resistance
versus temperature, the calculated resistance value to which the potentiometer R2 must be set in order to balance the
bridge at 60°C is:
4.4 kohms
If an object were caught in the upward movement of the car window, stalling the motor, what effect would this have on
the control circuit shown below?
Increase in VR. AND Increase in IMOTOR.
There are metal work pieces on a circular conveyor belt. The position of the work piece carrier is detected by a switch
that is magnetically sensitive. The block diagram of the sensor is shown below:
C
For the limit switch, as shown below, the contacts are indicated by numbers. Which of the shown electrical contact
symbols is correct?
A
Which of the following statements about the circuit shown below are correct?
Neither the positive nor the negative terminal of the single source Vs is connected to ground. AND The circuit
produces both positive and negative voltages from a single source Vs.
By reading the multimeters in the electrical circuit shown below, determine the type of failure in the circuit and which
component failed.
There is a solder splash short circuit between point A and point B.
To measure electrical ...
current, the ammeter must be in series with the current path.
As shown below, a through-beam sensor with fiber-optic cable is used to detect parts on a workpiece carrier. If no part
is present, the sensor sends a high signal to the PLC. Which of the following statements about the operation of the
sensor are correct?
It is possible to detect completely transparent work pieces. AND A broken fiber-optic cable at the light emitter is
evaluated as "work piece present".
An automotive application involves an inductive sensor that detects the crankshaft positionto adjust the fuel control
system. The result of a test measurement at the output of thesensor is shown below. The magnitude and rotational
speed are ...
˜ 1.2 V, 3000 r.p.m.
Which of the following statements about the functionality of the emergency lighting circuit, as shown below, are
correct?
The lamp will be connected to the storage battery as long as the relay remains de-energized. AND As long as the main
power is available, it energizes the relay coil.
Which statements about the mode of operation of a reflective light barrier shown below are correct?
The interruption of the light beam by an object causes the output of the sensorto switch. AND Failure of the
transmitter is evaluated as "object present".
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