fig1 shows the configuration of a liquid ejection apparatus 10 . the liquid ejection apparatus 10 is medical equipment used in medical institutions , and has a function of incising or resecting the lesion by ejecting liquid to the lesion . the liquid ejection apparatus 10 includes a liquid ejection mechanism 20 , a liquid supply mechanism 50 , a suction device 60 , a control device 70 , and a liquid container 80 . the liquid supply mechanism 50 and the liquid container 80 are connected to each other through a connection tube 51 . the liquid supply mechanism 50 and the liquid ejection mechanism 20 are connected to each other through a liquid supply passage 52 . the connection tube 51 and the liquid supply passage 52 are formed of resin . the connection tube 51 and the liquid supply passage 52 may be formed of materials ( for example , metal ) other than resin . the liquid container 80 contains a saline solution . instead of the saline solution , pure water or a chemical solution maybe used . the liquid supply mechanism 50 supplies liquid , which is suctioned from the liquid container 80 through the connection tube 51 , to the liquid ejection mechanism 20 through the liquid supply passage 52 by the driving of a built - in pump . the liquid ejection mechanism 20 is a device that the user of the liquid ejection apparatus 10 operates while holding it in his or her hand . the user incises or resects the lesion by applying the liquid , which is intermittently ejected from the liquid ejection mechanism 20 , to the lesion . the liquid ejection mechanism 20 is a disposable product , and is replaced with a new product for each operation . in the present embodiment , the liquid ejection mechanism 20 ( high power type liquid ejection mechanism 20 ) in which the excision capacity is set to be high and the liquid ejection mechanism 20 ( low power type liquid ejection mechanism 20 ) in which the excision capacity is set to be low are prepared as new liquid ejection mechanisms 20 . the user selects and prepares any of the liquid ejection mechanisms 20 according to an excision part or the like before the operation . the liquid ejection mechanism 20 includes a storage unit 40 . the storage unit 40 stores a liquid ejection mechanism id ( hereinafter , abbreviated as an “ id ”). a unique id is assigned to each liquid ejection mechanism 20 . the id includes information by which the high power type liquid ejection mechanism 20 or the low power type liquid ejection mechanism 20 can be determined . the suction device 60 is used for suction of liquid or a resected part around an ejection port 58 . the suction device 60 and the liquid ejection mechanism 20 are connected to each other through a suction passage 62 . the suction device 60 suctions the inside of the suction passage 62 consistently while a switch for operating the suction device 60 is on . the suction passage 62 passes through the inside of the liquid ejection mechanism 20 and is open in the vicinity of the tip of an ejection tube 55 . the suction passage 62 is covered by the ejection tube 55 extending from the tip of the liquid ejection mechanism 20 . therefore , as shown in a diagram viewed from the arrow a of fig1 , the wall of the ejection tube 55 and the wall of the suction passage 62 form approximately concentric cylinders . between the outer wall of the ejection tube 55 and the inner wall of the suction passage 62 , a passage through which a suctioned material , which is suctioned from a suction port 64 that is a tip of the suction passage 62 , flows is formed . the suctioned material is suctioned into the suction device 60 through the suction passage 62 . the liquid supply passage 52 , the suction passage 62 , and a signal cable 72 ( hereinafter , these three are referred to collectively as “ cables ”) are fixed to the liquid ejection mechanism 20 , and are replaced together with the liquid ejection mechanism 20 . when using the new liquid ejection mechanism 20 , the liquid ejection mechanism 20 to which cables are connected is prepared , and the cables are connected to respective connection destinations . when the user turns on a foot switch 75 in a state where cables are connected , the control device 70 transmits a driving signal to a pulsation generating unit 30 , which is built into the liquid ejection mechanism 20 , through the signal cable 72 . when the driving signal is input , the pulsation generating unit 30 generates a pulsation for the pressure of the supplied liquid . by this pulsation , intermittent ejection of the liquid described above is performed . the pulsation generating unit 30 generates the pulsation using the expansion and contraction of an actuator built therein . the actuator is configured by a piezoelectric element . the driving signal is for expanding and contracting the piezoelectric element . here , the ejection of liquid when the foot switch 75 is turned on as described above occurs while the control device 70 is set to a permission mode . the control device 70 sets itself to either the permission mode or a non - permission mode . in the non - permission mode , even if the foot switch 75 is turned on , the control device 70 does not drive the pulsation generating unit 30 and the liquid supply mechanism 50 . accordingly , in the non - permission mode , no liquid is ejected . the default mode of the control device 70 is a non - permission mode . switching to the permission mode is performed when a test process ( which will be described later with reference to fig3 and 4 ) is performed after the connection of the signal cable 72 and the test is passed . the permission mode is maintained until the signal cable 72 is removed after the switching to the permission mode . fig2 is a block diagram showing the internal configuration of the control device 70 , and shows a state in which the control device 70 and the liquid ejection mechanism 20 are connected to each other through the signal cable 72 . the control device 70 includes a control unit 90 , a monitoring unit 91 , a signal output unit 92 , a relay 93 , a first and circuit 98 , and a second and circuit 99 . the relay 93 is an electromagnetic relay , and includes a contact point 96 and an actuating coil 97 . the control unit 90 is formed by a microcomputer , and includes a nonvolatile memory ( for example , an feram ). the control unit 90 instructs the signal output unit 92 to output a driving signal . the signal output unit 92 outputs the driving signal when the instruction is received . the driving signal output from the signal output unit 92 is input to the monitoring unit 91 and the relay 93 . in a state where the contact point 96 is closed ( hereinafter , referred to as “ when the relay 93 is on ”), the driving signal passes through the relay 93 and is then input to the pulsation generating unit 30 through the signal cable 72 . the monitoring unit 91 monitors the driving signal before being input to the relay 93 . the monitoring unit 91 measures the voltage value and the current value of the driving signal , and inputs the measurement result to the control unit 90 . the monitoring unit 91 outputs a value h , which indicates that each of the voltage value and the current value is equal to or greater than a set threshold value , and a value l , which indicates that each of the voltage value and the current value is less than the set threshold value . in fig2 , for convenience of illustration , digital signals for the voltage value and the current value are collectively shown as a “ monitoring signal ”. the threshold value described above is a variable value set by the control unit 90 . the digital signal output from the monitoring unit 91 is input to the control unit 90 , and is input to the first and circuit 98 and the second and circuit 99 after being inverted . this inversion is performed by an inverter element . the control unit 90 performs switching between on and off ( state in which the contact point 96 is open ) of the relay 93 by inputting a switching signal to the actuating coil 97 of the relay 93 through the second and circuit 99 . the contact point 96 is a normally open contact point . accordingly , the relay 93 is on when the switching signal is input , and is off when the switching signal is not input . the switching signal is input to the actuating coil 97 when the value l is input to the second and circuit 99 as a monitoring signal for both the voltage value and the current value . that is , when a value equal to or greater than the threshold value , for at least one of the voltage value and the current value of the driving signal , is detected by the monitoring unit 91 , the relay 93 is turned off to stop the driving signal . the control unit 90 inputs a permission signal to the signal output unit 92 through the first and circuit 98 when an output instruction is given to the signal output unit 92 . even if the output instruction is given , the signal output unit 92 does not output a signal unless a permission signal is input . the permission signal is input to the signal output unit 92 when the value l is output as a monitoring signal for both the voltage value and the current value . that is , when a value equal to or greater than the threshold value , for at least one of the voltage value and the current value of the driving signal , is detected by the monitoring unit 91 , no driving signal is output . when at least one of the voltage value and the current value input from the monitoring unit 91 is equal to or greater than a predetermined value , the control unit 90 stops the output of an output instruction , a permission signal , and a switching signal . if these outputs are stopped , no driving signal is input to the pulsation generating unit 30 . by the monitoring function of the control unit 90 and the monitoring unit 91 described above , a driving signal due to excessive voltage or current is not input to the pulsation generating unit 30 . it is preferable to check as often as possible whether or not the monitoring function works normally . in the present embodiment , this checking is performed as a test process , which will be described later , whenever the new liquid ejection mechanism 20 is used . fig3 and 4 are flowcharts showing the test process . the test process is performed by the control unit 90 when the liquid ejection mechanism 20 is connected to the control device 70 through the signal cable 72 . the control device 70 detects a connection to the liquid ejection mechanism 20 based on a change in the electric potential of the connection line of the signal cable 72 connected to the storage unit 40 . the change in the electric potential is caused by a pull - up resistor and a pull - down resistor . as will be described later , when the test in this process is passed , the control device 70 proceeds to the permission mode from the non - permission mode . first , an id is acquired from the storage unit 40 ( step s 310 ). then , it is determined whether or not the acquired id is a new id ( step s 320 ). specifically , when the acquired id does not match any id stored in the control unit 90 , it is determined that the acquired id is a new id . when the acquired id matches one of the ids stored in the control unit 90 , it is determined that the acquired id is not a new id . the storage of the id is performed in step s 330 to be described later . when the acquired id is not a new id ( step s 320 ; no ), it is reported that the liquid ejection mechanism 20 that has been connected to the control unit 90 before is connected ( step s 490 ), and the test process is ended . here , the reporting of abnormalities is performed by outputting a message , such as “ please replace the liquid ejection mechanism with a new one ”. the output of the message is performed by display or voice . the output of the display or voice is performed by using a display or a speaker provided in the control device 70 . such a reporting using a message is performed because the acquired id is not a new id , and accordingly , it is estimated that the liquid ejection mechanism 20 is a used one . in this case , since a non - permission mode is maintained , the ejection of liquid by the liquid ejection mechanism 20 is not performed . on the other hand , when the acquired id is a new id ( step s 320 ; yes ), the acquired id is stored in a storage medium ( step s 330 ). then , a voltage test is performed ( step s 340 ). the voltage test is to test whether or not a voltage is generated from the signal output unit 92 according to the output instruction from the control unit 90 in a state where off of the relay 93 is maintained . whether or not a voltage is generated according to the output instruction is determined by comparing the output instruction given to the signal output unit 92 with a voltage value input from the monitoring unit 91 . when the voltage test is not passed ( step s 350 ; no ), the above - described step s 490 is performed . in this case , failure of the voltage , necessity of repair , or the like is reported . even if an excessive voltage is generated , the application of the voltage to the pulsation generating unit 30 is avoided since the relay 93 is set to off . on the other hand , when the voltage test is passed ( step s 350 ; yes ), the control unit 90 waits until a setup button is pressed ( step s 360 ). the setup button is an input interface provided in the control device 70 , and the user is requested to press the setup button after connecting the liquid ejection mechanism 20 . since a subsequent test is performed by turning on the relay 93 , a voltage is applied to the pulsation generating unit 30 . therefore , in order to call a user &# 39 ; s attention , pressing of the setup button is requested . in addition , since the liquid supply mechanism 50 is not driven in the test process , no liquid is ejected from the liquid ejection mechanism 20 . after the setup button is pressed , a short circuit test is performed ( step s 370 ). the short circuit test is a test for checking whether or not a short circuit has occurred in the connected liquid ejection mechanism 20 . fig5 a to 5e are graphs showing various waveforms in the short circuit test . fig5 a shows a temporal change of the voltage of a short circuit test signal . fig5 b shows a temporal change of the current in the normal state . the normal state referred to herein means that no short circuit occurs in the signal cable 72 and the like . fig5 c shows a monitoring signal as a current monitoring result in the normal state . fig5 d shows a temporal change of the current when a short circuit occurs . fig5 e shows a monitoring signal as a current monitoring result when a short circuit occurs . as shown in fig5 a , the waveform of the short circuit test signal is a trapezoidal shape . that is , the voltage of the short circuit test signal rises linearly up to a voltage v 1 , and the voltage v 1 is maintained for a predetermined amount of time . after the predetermined amount of time has passed , the voltage of the short circuit test signal drops linearly until the voltage becomes 0 . the voltage v 1 is set to a voltage much lower than the maximum voltage of the driving signal ( for example , 1 / 10 or less of the maximum voltage of the driving signal ) in consideration of a possibility of a short circuit . by setting the voltage v 1 to a voltage much lower than the maximum voltage of the driving signal , it is possible to suppress the damage to the electrical circuit or the malfunction of the electrical circuit even if a short circuit occurs . the short circuit test signal is input to the piezoelectric element . as shown in fig5 b , a positive current flows during a period for which the voltage rises linearly , no current flows during a period for which the voltage is maintained at the voltage v 1 , and a negative current flows during a period for which the voltage drops linearly . being maintained at the voltage v 1 means falling within the range of a predetermined voltage value . in the short circuit test , a threshold value th 1 is set for the current value . the monitoring unit 91 outputs the value l when the current value is maintained at a value less than the threshold value th 1 , and outputs the value h when the current value reaches the threshold value th 1 . as shown in fig5 b , the threshold value th 1 corresponds to a value of current that does not flow at the voltage v 1 in the normal state . therefore , in the normal state , the monitoring signal is maintained at the value l . when the monitoring signal is maintained at the value l , the control unit 90 determines that the state is normal since a short circuit has not occurred . on the other hand , when a short circuit occurs , as shown in fig5 d , the current value reaches the threshold value th 1 immediately after the input of the short circuit test signal . when the current value reaches the threshold value th 1 , a protection function of the control unit 90 and the monitoring unit 91 operates as described above . therefore , as shown in fig5 d , the current value becomes 0 after reaching the threshold value th 1 . the control unit 90 determines that a short circuit has occurred when the monitoring signal reaches the value h . the threshold value for the voltage value is set to a value larger than the maximum voltage so as not to interfere with the determination based on the current value . this is also the same for all subsequent tests . the short circuit test is performed as described above , and the above - described step s 490 is performed when the test is not passed ( step s 380 ; no ). in this case , a message , such as “ abnormality has been detected in the liquid ejection mechanism . please replace it ”, is output . when the short circuit test is passed ( step s 380 ; yes ), a disconnection test is performed ( step s 410 ). the disconnection test is a test for checking whether or not disconnection has occurred in the signal cable 72 or the like . fig6 a to 6c are graphs showing various waveforms in the disconnection test . fig6 a shows a temporal change of the voltage of a disconnection test signal . fig6 b shows a temporal change of the current in the normal state . the normal state referred to herein means that no disconnection occurs in the signal cable 72 and the like . fig6 c shows a temporal change of the current when disconnection occurs . as shown in fig6 a , the waveform of the disconnection test signal is a trapezoidal shape in the same manner as the short circuit test signal , and the maximum voltage is a voltage v 2 . the voltage v 2 is higher than the voltage v 1 that is the maximum voltage of the short circuit test signal , and is lower than the maximum voltage of the driving signal . as shown in fig6 b , the waveform of the current value in the normal state is stepwise as in the case of the short circuit test . when the current value is equal to or greater than the threshold value th 2 , the control unit 90 determines that the state is normal since disconnection has not occurred . the threshold value th 2 corresponds to a current value lower than a value of current that flows at the voltage v 2 if disconnection does not occur . the threshold value th 2 is not a threshold value set in the monitoring unit 91 but is a value that the control unit 90 adopts as criteria . this is because , if the threshold value th 2 is set in the monitoring unit 91 , the current value becomes 0 immediately after the start of a test , and accordingly , it is difficult to determine whether or not the state is normal . the threshold value set in the monitoring unit 91 in the disconnection test is set to a larger value than the current value generated in the disconnection test . on the other hand , the current value when disconnection occurs is maintained at 0 , as shown in fig6 c . thus , when the current value does not reach the threshold value th 2 , the control unit 90 determines that disconnection has occurred . when the disconnection test is not passed ( step s 420 ; no ), the above - described step s 490 is performed . also in this case , failure of the wiring system , necessity of repair , or the like is reported . when the disconnection test is passed ( step s 420 ; yes ), the test conditions of an overcurrent test are determined based on the acquired id ( step s 430 ), and the overcurrent test is performed ( step s 440 ). the overcurrent test is a test for checking whether or not the protection function described above operates normally when a current equal to or higher than the set threshold value is generated . the overcurrent test and the test conditions will be described with reference to fig7 a to 7c . fig7 a to 7c are graphs showing various waveforms in the overcurrent test . fig7 a shows a temporal change of the voltage in an overcurrent test signal . fig7 b shows a temporal change of the current in the overcurrent test signal . fig7 c shows a temporal change of the monitoring signal in the overcurrent test . a solid line j in fig7 a and 7b indicates a case of the low power type liquid ejection mechanism 20 , and a broken line b indicates a case of the high power type liquid ejection mechanism 20 . in the case of the low power type liquid ejection mechanism 20 , a current equal to or higher than a threshold value th 3 shown in fig7 b is regarded as an overcurrent , and the threshold value th 3 is set in the monitoring unit 91 . then , as shown in fig7 a , a driving signal having a voltage v 3 as a maximum voltage is output as the overcurrent test signal for a predetermined amount of time . the voltage v 3 is five times or more than the voltage v 1 . the driving signal is a driving signal output in the use mode , and does not generate a current equal to or greater than the threshold value th 3 as shown in fig7 b . the predetermined amount of time is an arbitrary time , and is illustrated as three periods of the driving signal in fig7 a . preferably , the voltage v 3 is 10 times or more than the voltage v 1 . when the voltage v 3 is 10 times or more than the voltage v 1 , the test can be performed more accurately . a driving signal having the voltage v 3 as a maximum voltage is output for a predetermined amount of time , and then a driving signal having a voltage v 4 as a maximum voltage is output . the voltage v 4 is a voltage value for generating a current equal to or greater than the threshold value th 3 . when the current equal to or greater than the set threshold value is generated , the value h is output as a monitoring signal , as shown in fig7 c . as described previously in the short circuit test , when the value h is output , the protection function of the control unit 90 and the monitoring unit 91 operates , and the current value becomes 0 as shown in fig7 b . the control unit 90 determines that the overcurrent test has been passed when the current becomes 0 as described above , and determines that the overcurrent test has not been passed when the current does not become 0 . the test conditions in the case of the low power type liquid ejection mechanism 20 include the threshold value th 3 , the voltage v 3 , and the voltage v 4 described above . in the case of the high power type liquid ejection mechanism 20 , as shown in fig7 a and 7b , a threshold value th 4 (& gt ; threshold value th 3 ), a voltage v 5 (& gt ; voltage v 3 ), and a voltage v 6 (& gt ; voltage v 4 ) are adopted instead of the threshold value th 3 , the voltage v 3 , and the voltage v 4 . the reason why the conditions are changed as described above is that , in the case of the high power type liquid ejection mechanism 20 , the maximum voltage of the driving signal is high , and accordingly , the current value regarded as the overcurrent is large . in addition , when the protection function operates as described above , the overcurrent test signal is interrupted and the voltage becomes 0 . in fig7 a , however , for convenience of explanation and description , the overcurrent test signal is output even after the protection function operates . when the overcurrent test is not passed ( step s 450 ; no ), the above - described step s 490 is performed . in this case , since a possibility of the failure of the control device 70 is high , failure of the control device , the necessity of repair , or the like is reported . when the overcurrent test is passed ( step s 450 ; yes ), an insulation test is performed ( step s 460 ). the insulation test is a test for checking whether or not the current is held at 0 when a voltage applied to the pulsation generating unit 30 is fixed , that is , when there is no ac component in the voltage . fig8 a to 8c are graphs showing various waveforms in the insulation test . fig8 a shows a temporal change of the voltage of an insulation test signal . fig8 b shows a temporal change of the current in the normal state . the normal state referred to herein means that insulation is successfully made . fig8 c shows a temporal change of the current when there is no insulation . as shown in fig8 a , the waveform of the insulation test signal is a trapezoidal shape in the same manner as the short circuit test signal and the disconnection test signal , and the maximum voltage is a voltage v 7 . the voltage v 7 is set to a value higher than the voltages v 1 to v 6 in order to test insulation . if the insulation is successfully made , no current flows while the voltage is held at the voltage v 7 , as shown in fig8 b . on the other hand , if there is no insulation , a current flows while the voltage is held at the voltage v 7 , as shown in fig8 c . when the current value equal to or greater than a threshold value th 5 is not detected , the control unit determines that the insulation is successfully made . similar to the threshold value th 2 in the disconnection test , the threshold value th 5 is a value adopted as criteria in the control unit 90 . when the insulation test is not passed ( step s 470 ; no ), the above - described step s 490 is performed . in this case , since the failure of the piezoelectric element is estimated as a cause of poor insulation , a message , such as “ abnormality has been detected in the liquid ejection mechanism . please replace it ”, is output . when the insulation test is passed ( step s 470 ; yes ), switching to the permission mode is performed ( step s 480 ), and the test process is ended . after the switching to the permission mode , liquid is ejected from the liquid ejection mechanism 20 by turning on the foot switch 75 . according to the present embodiment , various tests of the liquid ejection mechanism 20 and the control device 70 can be performed before the operation . by the tests , it is possible to prevent the used liquid ejection mechanism 20 from being reused or to prevent the operation from being performed in a state where there is an abnormality . when an abnormality is detected , it is possible to prompt the user to perform replacement or repair . in addition , in the overcurrent test , it is possible to perform a test according to the output type of the liquid ejection mechanism 20 . the short circuit test in the embodiment corresponds to a first test step in the aspects of the invention . the overcurrent test in the embodiment corresponds to a second test step in the aspects of the invention . the voltage v 1 corresponds to a first voltage , and the voltages v 5 and v 6 correspond to a second voltage . in the present embodiment , whenever the liquid ejection mechanism 20 that has never been used is connected to the control device 70 , anyone of the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test may be performed . thus , safe and reliable medical equipment can be provided for each operation . in addition , the control device 70 may perform the voltage test when a predetermined amount of time has passed , and any one of the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test may be performed whenever the liquid ejection mechanism 20 that has never been used is connected to the control device 70 . for example , the control device 70 includes a timer , and performs a voltage test when the liquid ejection mechanism 20 that has never been used is connected to the control device 70 after 24 hours since the use . in this case , even if a plurality of liquid ejection mechanisms 20 are connected to the control device 70 within 24 hours , the liquid ejection apparatus can be used earlier since the voltage test can be omitted . the invention is not limited to the embodiments , examples , or modification examples of this specification , and various configurations can be implemented without departing from the spirit and scope of the invention . for example , in order to solve some or all of the problems described above or to achieve some or all of the effects described in this specification , technical features in the embodiments , examples , and modification examples corresponding to the technical features described in the aspects of the invention may be appropriately replaced or combined . the technical features can be appropriately deleted if the technical features are not described as essential ones . for example , the following may be mentioned . although the id is acquired from the storage unit 40 and it is determined whether or not the acquired id is a new id ( step s 320 ), the invention is not limited thereto . specifically , an id allowing the connection to the control unit is stored in advance , and the control unit 90 stores connection history when the liquid ejection mechanism 20 is connected to the control unit 90 . then , when the liquid ejection mechanism 20 that has been connected before is connected again , the test process may be ended , and a test of the liquid ejection mechanism 20 that has never been connected may be performed . instead of the connection history , a period for which the control unit 90 uses the liquid ejection mechanism 20 or a period for which the liquid ejection mechanism 20 is connected to the control unit 90 may be stored , or one or more of the connection history , the use period , and the connection period may be stored . specifically , when the liquid ejection mechanism 20 is connected to the control unit 90 , the control unit 90 stores one or more of the connection history , the use period , and the connection period . then , one or more items regarding whether or not there is connection history , whether or not a predetermined use period has expired , and whether or not a predetermined connection period has expired may be checked . when the liquid ejection mechanism . 20 corresponding to one or more of the items is connected again , the test process may be ended , and the liquid ejection mechanism 20 that does not correspond to one or more of the items may be tested . by storing the use period or the connection period of the liquid ejection mechanism 20 , the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test can be performed even if the liquid ejection mechanism 20 is attached and detached multiple times in one operation . by performing the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test whenever the liquid ejection mechanism 20 is connected or at predetermined time intervals , it is possible to provide safe and reliable medical equipment . as a test of the electrical system of the liquid ejection mechanism 20 , a current test maybe performed in addition to the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test . the current test may also be performed instead of the voltage test . at least two of the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test , for example , the disconnection test and the insulation test may be performed using the same test signal . it is preferable to perform the disconnection test , the overcurrent test , and the insulation test after performing the voltage test and the short circuit test . in this case , the voltage test and the short circuit test may be performed in any order , and the disconnection test , the overcurrent test , and the insulation test may be performed in any order . some of the voltage test , the short circuit test , the disconnection test , the overcurrent test , and the insulation test may not be performed . when the short circuit test is not performed , the disconnection test may be performed as a first test step . the insulation test maybe performed as a second test step . in this case , the voltage used in the insulation test may be changed according to the type of the liquid ejection mechanism . a test corresponding to the second test step may be performed under the same conditions regardless of an id . id acquisition may be performed at any time before the test corresponding to the second test step . for example , the id acquisition may be performed after the short circuit test or may be performed after the disconnection test . the magnitude relationship of the voltages in the test signals shown in the embodiment is just an example , and may be changed . the waveform of the signal used in each test may be changed . for example , the waveform of the signal used in each test may be changed to a triangular wave . the success / failure determination in each test is not limited to that illustrated in the embodiment , but various determinations may be considered . for example , in the overcurrent test , success or failure may be determined based on the fact that the control unit can detect the overcurrent successfully even if the current is not actually interrupted . the liquid ejection mechanism and the cables may not be fixed . for example , the cables may be fixed to the control device , the liquid supply mechanism , and the suction device . there maybe three or more output types of the liquid ejection mechanism . an identifier may be used to identify the liquid ejection mechanism described in the embodiment and other liquid ejection mechanisms . as other liquid ejection mechanisms , it is possible to use a liquid ejection mechanism that is used for an endoscope , such as a laparoscope , and is inserted into the body and is operated . the liquid ejection apparatus may be used for apparatuses other than the medical equipment . for example , the liquid ejection apparatus may be used for a cleaning apparatus that removes dirt with the ejected liquid . the liquid ejection apparatus may be used for a drawing apparatus that draws a line or the like with the ejected liquid . as a liquid ejection method , laser light may be used . as an ejection method using the laser light , for example , it is possible to apply a method using a pressure variation due to the evaporation of the liquid caused when emitting the laser light intermittently to the liquid .
a control device is connectable to a surgical instrument , and controls the surgical instrument . when the surgical instrument is connected , the control device determines the quality of the surgical instrument by performing a plurality of different tests .