JPS628013A - Apparatus for adjusting engine monitor - Google Patents

Abstract

PURPOSE:To simplify the adjustment preparation of an engine monitor and to facilitate the maintenance thereof, by outputting the zero and span adjusting signals of each monitor part of the engine monitor by a signal generation means. CONSTITUTION:A first signal generation means outputs the zero and span adjusting signals of the temp. monitor part of an engine monitor and a second signal generation means outputs the zero and span adjusting signals of the pressure monitor part of the engine monitor. Further, a third signal generation means outputs the zero and span adjusting signals of the number-of-rotation monitor part of the engine monitor. A measuring control means measures the zero and span adjusting signals outputted from the signal generation means corresponding to an adjusting object selected by adjusting object selection switches 8a-8d. A display control means forms a display signal on the basis of the measured value measured by said measuring means and supplied the same to a display means 13 which, in turn, displays the zero and span adjusting signals and/or the temp. and pressure corresponding thereto.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an engine monitor adjustment device.

Conventional technology and its problems Engine monitors include a temperature monitor section that measures and displays the temperature based on the detection signal of a temperature detector installed on the engine side, and a temperature monitor section that measures and displays the temperature based on the detection signal of a pressure sensor installed on the engine side. A pressure monitor section that measures and displays the pressure based on the pressure and a rotation speed monitor section that measures and displays the rotation speed based on a detection signal from a rotation speed detector provided beside the engine are provided.

In order to perform zero and span adjustment for each monitor section of the engine monitor, it is necessary to supply zero and span adjustment signals to each monitor section. Conventionally, separate zero and span adjusters have been used for each monitor section to supply zero and span adjustment signals to each monitor section.

Therefore, when adjusting the engine monitor, it is necessary to prepare a plurality of different types of regulators, which is troublesome to prepare and also inconvenient to store each regulator.

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine monitor adjustment device that facilitates preparation for adjusting an engine monitor and is convenient for storage.

Means for Solving the Problems The engine monitor adjustment device according to the present invention includes: zero and span adjustment signals for the temperature monitor section of the engine monitor; first signal generation means for outputting signals for adjusting the span; and a pressure monitor section for the engine monitor. a second signal generation means for outputting signals for zero and span adjustment of the engine monitor, a third signal generation means for outputting signals for zero and span adjustment of the rotation speed monitor section of the engine monitor, for zero and span adjustment; A measuring means for measuring the signal, a display device for displaying the zero and span adjustment signals and/or the corresponding temperature, pressure or rotation speed, an adjustment target selection switch,
measurement control means for causing the measurement means to measure zero and span adjustment signals output from the signal generation means corresponding to the adjustment object selected by the adjustment object selection switch;
The present invention is characterized by comprising display control means for creating a display signal based on the measurement value measured by the measurement means and supplying it to a display device. Here, the zero and span adjustment signals include resistance as well as voltage signals, current signals, and frequency signals.

Embodiment [1] Structure of operation surface of engine monitor adjustment device FIG. 1 shows the external appearance of the engine monitor adjustment device. This engine monitor adjustment device uses zero and span adjustment signals for the temperature monitor, rotation speed monitor, and pressure monitor of the engine monitor (here, the signals include voltage signals, frequency signals, current signals, as well as resistance). ), a function to measure the generated zero/span adjustment signals, and a function to display the measured values and the corresponding temperature, rotation speed, or pressure.

The rotation speed monitor section measures and displays the rotation speed based on the detection signal of a rotation speed detector that outputs a voltage signal corresponding to the rotation speed (hereinafter referred to as the voltage type rotation speed monitor section).
and a device that measures and displays the rotation speed based on the detection signal of a rotation speed detector that outputs a frequency signal corresponding to the rotation speed (hereinafter referred to as a frequency type rotation speed monitor section). The rotation speed monitor section can be adjusted.

On the left side of the operation surface of the engine monitor adjustment device, there are terminals (
3a) and (3b) are provided in order from the top.

On the right side of the operation surface, there are terminals (4a) (4b) for connecting the temperature monitor section of the engine monitor, terminals (5a) (5b) for connecting the voltage type rotation speed section, and terminals for connecting the frequency type rotation speed monitor section. (6a) (6bH6c) and pressure monitor section connection terminals (7a) (7b) are provided in this order from the top.

In the center of the operation surface, there are four process selection keys for selecting one of temperature monitor part adjustment processing, voltage type rotation speed monitor part adjustment process, pressure monitor part adjustment process, and frequency type rotation speed monitor part adjustment process. A group (8a) to (8d) is provided.

At the left side of the process selection key group (8a) to (8d) on the operation surface, there is a zero adjustment button switch (9) that is operated when adjusting the temperature monitor section, and a first button switch for span adjustment.
A push button switch (10), a second push button switch (11) for span adjustment, and a group of current selection keys for resistance value measurement (
12a) to (12d) are provided.

Above the processing selection keys (8a) to (8d) on the operation surface, there is a display (13) for displaying the measured value of the zero/span adjustment signal and the temperature corresponding to the measured value.
is provided. As this display (13), for example, a light emitting diode type numeric display or a liquid crystal display is used.

Display (13) (7) Right side Niha Ω, °C, mV, V,
rpm.

A plurality of unit indicator lights (14) are provided to display units such as mA, 9f/cj, and Kpa. display(
On the left side of 13), whether to display the measured values of the zero span adjustment signal such as resistance value, voltage value, and current value on the display (13), or to display direct reading values such as temperature rotation speed and pressure corresponding to the measured value. A measured value selection key (15) and a direct reading value selection key (16) are provided for selecting the desired value. A pressure unit selection key (17) is provided below these keys (15016) for selecting whether the pressure value is expressed in kgf/ci or in pa. On the right side of the unit indicator group (14),
A measurement function abnormality indicator light (alarm indicator light) (18), its reset push button switch (19) and a scale over indicator light (20) are provided.

To the left of the connection terminals (4a) to (7b) on the right side of the operation surface is a resistance value adjustment dial (2) for adjusting the temperature monitor.
1), a voltage value adjustment dial (22) for adjusting the voltage-type rotation speed monitor section, a pulse frequency adjustment dial (23) and a pulse duty ratio adjustment dial (24) for adjusting the frequency-type rotation speed monitor section (24). A current adjustment dial (25) for adjusting the pressure monitor unit is provided in order from the top.

To the left of the resistance value adjustment dial (21) is a temperature full scale setter (26), and to the left of the voltage value adjustment dial (22) are a voltage range selection key (27) and a rotation speed full scale setter. (28) is the frequency adjustment dial (2
3) is provided with a turning gear ratio setting device (29), and a pressure full scale setting device (30) is provided below the process selection key group (8a) to (8d). Also, on the right side of terminals (3a) and (3b) are terminals (3
a) A via pushbutton switch (31) is provided for connecting (3b) and terminals (7a) and (7b) to each other.

The case of the engine monitor adjustment device is designed to protect the operating surface! '(32) is attached so that it can be opened and closed.

[2] Figure 2 shows the electrical configuration of the engine monitor adjustment device.
The electrical configuration of the engine monitor adjustment device is shown.

The engine monitor adjustment device includes a power supply section (41), a temperature monitor section adjustment section (42) 1, a voltage type rotation speed monitor section adjustment section (43), and a frequency type rotation speed monitor section adjustment section (44).
, pressure monitor adjustment section (45), measurement data creation section (
46), a display and operation section (41), a control section (48), and the like.

The power supply unit (41) includes a rectifier (49), a storage battery (50),
Operating voltage generation circuit (51) and operating voltage monitoring circuit (5
2). The operating voltage monitoring circuit (52) monitors whether each operating voltage output from the operating voltage generating circuit (51) is normal, and if it is normal,
The operating voltage normal indicator light (2) is lit.

The temperature measurement display adjustment section (42) is a current generator (53).
and a resistance circuit (54). 'R current generator 53) has a group of current selection keys (12a) to (12d).
The current value selected by (in this example, 20μA,
outputs a signal of 200 μA, 21 A, and 5 mA). The resistance circuit (54) includes a zero adjustment resistor (55), a span adjustment variable resistor (56), and changeover switches (57) to (63). The resistance value of the variable resistor (56) is adjusted by the resistance adjustment dial (21). Push button switch for zero adjustment (9)
is operated, the changeover switch (57) (58
) (59) is switched.

When the first adjustment push button switch (10-) is operated, the changeover switches (59) (60) (61) (6
2) can be switched. The changeover switch (
63) is switched.

The voltage-based rotation speed monitor adjustment section (43) includes a voltage generator (64) and a voltage range switching key (27). The voltage generator (64) has a voltage adjustment dial (2
2), a low voltage output terminal that outputs a voltage between O and 100 nV adjusted by the voltage adjustment dial (22), a high voltage output terminal and a negative output terminal that output a voltage between O and 10 v that was output by the voltage adjustment dial (22). We are prepared. The low voltage output terminal and high voltage output terminal are connected to the voltage range selection key (2).
7) are connected to fixed contacts (27a) and (27b), respectively.

A terminal (27c) on the contact side of the switching key (27) is connected to a connection terminal (5a). The negative output terminal is connected to the connection terminal (5b). Although not shown, a changeover switch is provided that operates in conjunction with a voltage range changeover key (27), and a voltage range designation signal from this switch is input to a CPU (80), which will be described later.

The frequency type rotational speed monitor section adjustment section (44) includes a variable frequency pulse generator (65). The frequency and duty ratio of the pulse signal output from the pulse generator (65) are adjusted by the frequency adjustment dial (23) and the duty ratio adjustment dial (24), respectively. The pulse generator (65) includes an output terminal for outputting a first pulse, an output terminal for outputting a second pulse whose phase is delayed by a predetermined angle from the first pulse, and a common terminal. Connection terminal (6a) (6b)
(6C) respectively. Pulse generator (
The output pulse of 65) is sent to the frequency measurement shift register (
66) is also sent.

The pressure monitor adjustment unit (45) has a current generator (67
), changeover switches (68) (69) operated by the via switch (31), and a current measuring resistor (for example, 50Ω) (70). Current generator (6
The current output from 7) is adjusted by the current adjustment dial (25). The positive output terminal of the current generator @ (67) is connected to the connection terminal (7a) via the b contact of the changeover switch (68). The negative output terminal of the current generator (67) is connected to the connection terminal (7b) via the b contact of the changeover switch (69) and the resistor (10).

The connection terminal (3a) is connected to the connection terminal (7b) via the a contact of the changeover switch (69) and the resistor (70). The connection terminal (3b) is connected to the connection terminal (7a) via the a contact of the changeover switch (68).

The measurement data creation section (46) includes an A/D conversion section (71) including an A/D converter, foundation amplifier, sample hold, decoder, etc., and a multiplexer (72).
It is equipped with The first human power section of the multiplexer (72) (
A1) is a reference resistance for determining the normality of the measurement function (for example, 1
00Ω) (73) is input. The voltage across the terminals of the resistor (70) of the pressure monitor adjustment section (45) is input to the second human power section (A2) of the multiplexer (72). The third human power section (A3) of the multiplexer (72)
) is inputted with the output voltage (voltage between the connection terminals (5a) and (5b)) of the voltage-type frequency monitor adjustment section (43). The fourth manual power section (A4) of the multiplexer (72) has a zero adjustment resistor (55) of the temperature monitor section adjustment section (42).
The voltage across the terminals of the span adjustment variable resistor (56) is input. The output terminal of the multiplexer (12) is connected to the A/D converter (71).

The display and operation section (47) includes a display (13), a group of unit indicator lights (14), an alarm indicator light (18), a scale over indicator light (20), and a group of process selection keys (8a) to (8).
d), full scale setting device (26) (28) (29
), a turning gear ratio setter (30), a measured value selection key (15), a direct reading value selection key (16), a pressure unit selection key (17), and a reset push button switch (19).

The control unit (48) includes a CPU (8G), a memory (81
), CT C (82), buffer (83), decoder (84) and input/output boat (85) (86) (87)
It is equipped with The A/D converter (71) is connected to the CPU (8G) via an input/output port (86). The shift register (66) is connected to CP tJ (80) via an input/output port (85). display(
13) is connected to the CPU (80) via the buffer (83).
It is connected to the. The unit indicator light group (14) is a decoder (
84) to the CPU (8G). Each indicator light, each key, each setting device, and pushbutton switch of the display and control section (47) is connected to the CPU (80) via an input/output board (87).

CP LJ (8G) is III i of various input/output devices.
ll, data conversion processing of measurement data into direct reading values, automatic calibration processing of temperature measurement data, etc. Memory (81)
The program, data conversion table, various data, etc. are stored in the .

[3] Zero-span adjustment of temperature monitor section The operation and operation of the adjustment device when performing zero-span adjustment of the temperature monitor section of the engine monitor will be explained.

Connect the detector connection terminal of the temperature monitor section of the engine monitor and the connection terminals (4a) (4b). Process selection key (8
a) Therefore, select the temperature monitor unit adjustment process, and use the current selection keys (12a) to (12d) to select the current generator (53).
) to set the output current. Further, the temperature full scale, for example, 160°C or 600°C is set in the setting device (26).

When temperature monitor unit adjustment processing is selected, CP tJ (
80) of the multiplexer (72).
A4) is selected and specified.

Next, press the zero adjustment push button switch (9). Then, the changeover switch (57) of the resistance circuit (54) (5B
) The B contact of (59) turns off, the A contact turns on, and the voltage between the terminals of the zero adjustment resistor (55) changes to the multiplexer (
72) to the A/D converter (71), where the A/D
converted. The A/D converted data is converted to CP Ll (
80), and based on this input data and the set full scale, it is determined whether the scale is over.

If the scale is over, the scale over indicator light (20)
is lit. Also, based on the input data, the resistance (5
The resistance value of 5) is measured and stored in the memory (81). In addition, the measured resistance value is compared with the resistance value (100Ω in this example) of the resistor (55) set in advance, and the difference is stored in the memory (81) as an offset amount.
is memorized.

If the measurement value selection key (15) is turned on, the offset correction value of the measured resistance value (in this example, 100
Ω) is displayed on the display (13), and a unit indicator light (14) representing the unit Ω is lit. When the direct reading value selection key (16) is turned on, the temperature corresponding to the offset correction value of the measured resistance value is determined, and this temperature is displayed on the display (13), as well as the unit expressed in °C. The indicator light (14) is turned on.

Next, release the zero adjustment push button switch (9). Then, the changeover switches (57) (58) (
59) is switched, and the resistor FC (55) is connected to the connection terminal (4).
a) Connected to (4b). This results in resistance (55)
is connected to the temperature monitor section of the engine monitor.

In this state, zero-adjust the temperature monitor section.

When the zero adjustment of the temperature monitor section is completed, press the first pushbutton switch (10) for span adjustment. Then, the changeover switches (59) (60) (61H62) of the resistance circuit (54)
) is turned off, the a contact is turned on, and the variable resistor (5
6) is passed through the multiplexer (12) to A
The signal is sent to the /D converter (11) and subjected to A/D conversion. A1
The 0-converted data is taken into the CPU (80), which determines whether or not it is overscaled and is processed by the variable resistor (56).
) is measured. Also, memory (81)
The measured resistance value is corrected on the basis of the offset value already stored in the memory.

If the measurement value selection key (15) is turned on, the offset correction value of the measured resistance value is displayed on the display (13) and the unit indicator light (14) indicating the unit Ω is lit. If the direct reading selection key (16) is turned on,
The temperature for the offset correction value of the measured resistance value is determined and displayed on the display (13) in degrees Celsius.
A unit indicator light (14) indicating .

The operator operates the resistance adjustment dial (21) while observing the resistance value or temperature displayed on the display (13), and the resistance value of the variable resistor (56) becomes the resistance value for span adjustment. Adjust as follows.

After this, press the first pushbutton switch (10) for span adjustment.
, and press the second span adjustment pushbutton switch (11). Then, the changeover switch (59) (6G) (61
) (62) returns to its original state and the selector switch (6
3) B contact turns off, A contact turns on, and the variable resistor (
56) is connected between the connection terminals (4aH4b). That is, the variable resistor (56) is connected to the temperature monitor section of the engine monitor. In this state, adjust the span of the temperature monitor section.

[4] Below the zero/span adjustment of the lightning voltage rotation speed monitor section, the zero/span adjustment of the voltage type rotation speed monitor section of the engine monitor
The operations for span adjustment and the operation of the adjustment device will be explained.

Connect the detector connection terminal and connection terminals (5a) and (5b) of the voltage type rotation speed monitor section of the engine monitor.

The voltage type rotation speed monitor section adjustment process is selected using the process selection key (8b), and the voltage range is selected using the voltage range selection key (21). Also, set the full scale on the setting device (28). When the voltage type rotational speed monitor section adjustment process is selected, the third manual section (A3) of the multiplexer (72) is selected and designated by the CPU (80). Therefore, the voltage between the connection terminals (5a)' (5b) (voltage supplied to the monitor section) is sent to the A/D conversion section (11) through the multiplexer (72) and A/D converted.

The A/D converted data is taken in by the CPU (80), and based on the input data, it is determined whether or not the scale is over, and if the scale is over, the scale over indicator light (20) is lit. .

When the voltage range of 0 to 1001V is selected by the range selection key (27) and the measurement value selection key (15) is turned on, the voltage supplied to the monitor unit (unit: a + V) is determined based on the input data. ) is determined and displayed on the display (13), and the unit indicator light (14) representing the unit ll1v is lit.

When the voltage range of 0 to 10V is selected and the measurement value selection key (15) is turned on, the voltage supplied to the monitor section (unit: V) is calculated based on the input data and displayed on the display. (13) and unit V
A unit indicator light (14) indicating .

When the direct reading value selection key (16) is turned on, the rotation speed (unit: rpm) corresponding to the input data is determined and displayed on the display (13), and the unit: rpm is determined. The unit indicator light (14) is lit.

The operator operated the voltage adjustment dial (22) while watching the voltage or rotation speed displayed on the display (13) to adjust the voltage supplied to the monitor section to a predetermined zero adjustment voltage value. Afterwards, zero adjustment of the voltage type rotational speed monitor section is performed. Also, after adjusting the voltage supplied to the monitor unit to the predetermined span adjustment voltage value by operating the dial (22),
Adjust the span of the monitor section.

[5] Zero/Span Adjustment of Frequency Type Rotation Speed Monitor Section The following describes the operation and operation of the adjustment device when performing zero/span adjustment of the frequency type rotation speed monitor section of the engine monitor.

Connect the detector connection terminal of the frequency type rotation speed monitor section of the engine monitor and the connection terminal (6a) (6bH6c).

After setting the turning gear ratio on the setting device (29) and setting the duty ratio using the duty ratio adjustment dial (24), select the frequency type rotation speed monitor unit adjustment process using the process selection key (8d). When the frequency type rotation speed monitor unit adjustment process is selected, the frequency of the output pulse of the variable frequency pulse generator (65) is measured by CP LJ (8G) based on the input signal from the register (66). Then, the rotation speed (unit: rpn+) corresponding to the measured frequency is determined and displayed on the display (13), and an indicator light (14) indicating the unit: rpl.
is lit.

The operator operates the frequency adjustment dial (23) while watching the rotation speed displayed on the display (13) to adjust the frequency of the pulse signal supplied to the monitor unit to the predetermined zero adjustment frequency. , Perform zero adjustment of the frequency type rotation speed monitor section of the engine monitor. Further, after adjusting the frequency of the pulse signal supplied to the monitor section to the frequency for span adjustment by operating the diol (23), span adjustment is performed.

(6) Zero-span adjustment of the pressure monitor unit The following describes the operation and operation of the adjustment device when performing zero-span adjustment of the pressure monitor unit of the engine monitor.

Connect the detector connection terminal of the pressure monitor section of the engine monitor and the connection terminal (7aH7b). If the pressure detector connected to the monitor section has a zero/span adjustment function, connect that detector to the connection terminals (3a) (3b). Select the pressure monitor adjustment process using the process selection key (8C), and set the full scale, for example, 1g/cd, 15Kg/cd, 30Kf/d, on the setter (30). When the pressure monitor adjustment process is selected, the CPU
(80) selects and designates the second human power section (A2) of the multiplexer (72). Therefore, the voltage between the terminals of the current measuring resistor (70) of the pressure monitor adjustment section (45) passes through the multiplexer (72) and the A/D conversion section (7
1) and undergoes A/D conversion. The A/D converted data is taken in by the CP tJ (80), and based on the input data, it is determined whether the scale is over or not, and if the scale is over, the scale over indicator light (20) is lit. .

When the measurement value selection key (15) is turned on, the current flowing through the resistor (70) (
The current supplied to the monitor section (unit: IRA) is determined and displayed on the display (13), and a unit indicator light (14) indicating the unit of mA is lit.

When the direct reading value selection key (16) is turned on and the unit Kgf/1-Ili is selected using the pressure unit selection key (17), the pressure corresponding to the data (unit Kgf /ad) is determined and displayed on the display (13), and the unit Ky
An indicator light (14) indicating T/cd is lit.

Direct reading value key (16) is turned on and pressure unit selection key is pressed.
If pa is selected as the unit in (17), the pressure (unit: kpa) corresponding to that data is calculated based on the above input data and displayed on the display (13), and the unit is pa. The indicator light (14) is lit.

If the pressure detector connected to the pressure monitor section does not have a zero/span adjustment function, leave the via pushbutton switch (31) in the OFF state. In this case, the output current of the current generator (67) is sent to the pressure monitor section via the b contacts of the changeover switches (68) and (69). While watching the pressure value or current value displayed on the display (13), operate the current adjustment dial (25) to adjust the current supplied to the pressure monitor section to the predetermined O3L maintenance current value. , Perform zero adjustment of the pressure monitor section. After adjusting the value of the current supplied to the pressure monitor section to a predetermined span adjustment current value by operating the dial (25), the pressure monitor section is zero-adjusted.

If the pressure detector connected to the pressure monitor section has a zero/span adjustment function, the operator presses the via pushbutton switch (31). Then, the B contacts of the changeover switches (68) and (69) turn off and the A contacts turn on, so that the pressure detector
) is connected to the pressure monitor unit. After that, apply zero adjustment pressure to the pressure detector. In this case, the current value detected by the pressure detector or the pressure value corresponding to the current value is displayed on the display (13), so zero adjustment is performed while watching this display. In addition, span adjustment is performed by applying pressure for span adjustment to the pressure detector and checking the display on the display (13).

Note that the measurement function normality determination reference resistance (73) is provided to determine whether the measurement function of the engine monitor adjustment device is normal.

That is, the resistance value of the resistor (73) is measured by the CPU (80) as appropriate based on the voltage between the terminals of the resistor (73).

Then, it is checked whether the measured resistance value is within a predetermined range centered on the resistance value of the resistor (73) set in advance, and if the measured resistance value is not within the predetermined range, the measurement function is exceeded. The indicator light (18) is turned on and the measured resistance value is displayed on the display (13). This allows the operator to determine whether the measurement function of the engine monitor adjustment device is normal.

Effects of the Invention With the engine monitor adjustment device according to the present invention, it is possible to perform zero and span adjustment of the temperature monitor section, pressure monitor section, and rotation speed monitor section of the engine monitor with one unit. Therefore, preparation for adjusting the engine monitor becomes easy, and storage becomes easy.

[Brief explanation of the drawing]

Figure 1 is a front view showing the appearance of the engine monitor adjustment device;
FIG. 2 is an electrical circuit diagram showing the electrical configuration of the engine monitor adjustment device. (8a) to (8d)...Group of processing selection keys, (13).
...Indicator, (21) ...Resistance adjustment dial, (22
)...Voltage adjustment dial, (23)...Frequency adjustment dial, (25)...Current adjustment dial, (41)
...power supply section, (42)...adjustment section for temperature monitor section,
(43)... Voltage type rotation speed monitor adjustment section, (44)
...Frequency type rotation speed monitor section, (45)...Pressure monitor section adjustment section, (46)...Measurement data creation section, (6
G)...Shift register, (8G)・CP Ll,
(81)...Memory. that's all

Claims (1)

[Scope of Claims] A first signal generating means for outputting zero and span adjustment signals for a temperature monitor section of an engine monitor; A first signal generating means for outputting zero and span adjustment signals for a pressure monitor section of an engine monitor; a third signal generating means for outputting signals for zero and span adjustment of the rotation speed monitor section of the engine monitor; a measuring means for measuring the signals for zero and span adjustment; zero and span adjustment. a display device for displaying the temperature, pressure, or rotational speed signal and/or the corresponding temperature, pressure, or rotational speed, an adjustment target selection switch, and the zero and span output from the signal generation means corresponding to the adjustment target selected by the adjustment target selection switch. An engine monitor adjustment device comprising: measurement control means for causing a measurement means to measure an adjustment signal; and display control means for creating a display signal based on the measurement value measured by the measurement means and supplying it to a display device.