Panasonic LT4H/-L Manual 

Also see for LT4H: Specifications

Contents

specifications

48Noise wave form (noise simulator)Rise time: 1 nsPulse width: 1 μs, 50 nsPolarity: ±Cycle: 100 cycles/second5) When connecting the operating powersupply, make sure that no leakage cur-rent enters the timer. For example, whenperforming contact protection, if set uplike that of fig. A, leaking current willpass through C and R, enter the unit,and cause incorrect operation. The fig. Bshows the correct setup.• Surge wave form[± (1.2 × 50) μs uni-polar full wave voltage]1009050300 0 1.2Time (μs)Surge voltage (%)50PeakTTCR(Fig. A)(Fig. B)Operating power supplyLeakage currentRCOperating power supplyLoad’spower supplyInductive loadLT4H timerDiode rating:IF (forward current): 1 AVR (reverse voltage): 600 VOnce the wiring to be used is completelyinstalled and prior to installing this timer,confirm that there is complete insulationbetween the wires connected to thepower terminals (2 each) and the wiresconnected to each input terminal. If thepower and input lines are not insulated, ashort-circuit may occur inside the timerand result in internal damage.In addition, when moving your equipmentto a new installation location, confirmthat there is no difference in environmen-tal conditions as compared to the previ-ous location.4) The input signal is applied by theshorting of each input terminal with thecommon terminal (terminal Q for 8-pintypes, terminal E for 11-pin types andterminal for screw terminal types).Never connect other terminals or volt-ages higher than 40V DC, because itmay destroy the internal circuitry.5) Transistor output(1) Since the transistor output is insulat-ed from the internal circuitry by a pho-tocoupler, it can be used as an NPNoutput or PNP (equal value) output.(The above example is 11-pin type)6LoadLoad’s power supplyLT4H timer{ O IAs NPN outputLoadLoad’s power supplyLT4H timerAs PNP output{ O I(2) Use the diode connected to the out-put transistor’s collector for absorbingthe reverse voltage from induced loads.6) When wiring, use shielded wires ormetallic wire tubes, and keep the wirelengths as short as possible.7) For the load of the controlled output,make sure that it is lower than the ratedcontrol capacity.4. Operation of LT4H digital timer1) Turning on and off the power supplywhile operating in A2* (Power on delay2) or G (Totalizing On delay) will result ina timer error to be generated due to thecharacteristics of the internal circuitry.Therefore, use the start input or stopinput.* Not related to the start input.2) When controlling the timer by turningon the power supply, use only A (Poweron delay 1) or A2 (Power on delay 2).Use of other modes in this situation willresult in timer errors. When using theother modes, control the timer with thestart input or stop input.5. Operation mode and time range set-tingThe operation mode and time range canbe set with the DIP switches on the sideof the timer. Make the DIP switch set-tings before installing the timer on thepanel.The operation mode of LT4H-W seriescan be set with the keys and switches onthe front of the timer.6. Conditions of usage1) Avoid locations subject to flammableor corrosive gases, excessive dust, oil,vibrations, or excessive shocks.2) Since the cover of the timer is made ofpolycarbonate resin, avoid contact withor use in environments containing methylalcohol, benzene, thinners, and otherorganic solvents; and ammonia, causticsodas, and other alkaline substances.3) If power supply surges exceed the val-ues given below, the internal circuits maybecome damaged. Be sure to use surgeabsorbing element to prevent this fromhappening.4) Regarding external noise, the valuesbelow are considered the noise-resistantvoltages. If voltages rise above thesevalues, malfunctions or damage to theinternal circuitry may result, so take thenecessary precautions.Operating voltage Surge voltage (peak value)AC type 6,000VDC type24V AC type 1,000VPower supply terminals InputterminalsAC type DC type24V AC typeNoisevoltage 1,500V 1,000V 600VNote: With the 8-pin type, there is no diodebetween points I and O.PRECAUTIONS IN USING THE LT4H SERIES(e.g., sensor)TimerTimerAC power supply(e.g., sensor)Input deviceInsulation transformerTimerInsulation transformer(Fig. B) Bad exampleAC power supply(Fig. A) Good exampleAC power supplyInput device(+)(–)(–)Input device(e.g., sensor)Alternativecurrent flowSingle coil transformer(+)(–)(+)(–)(–)(–)

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