PHILIPS PM3375 (01) PDF Document

The PHILIPS PM3375 Digital Storage Oscilloscope (DSO) features a combination of analog and digital capabilities. Its main features include:

– 100 MHz analog oscilloscope functionality.

– 100 Msamples/s single shot digital acquisition on both channels for the PM3350A and PM3365A models, and 250 Msamples/s for the PM3355 and PM3375 models.

– Auto Set for instant signal viewing in both analog and digital oscilloscope modes.

– Cursors for time and amplitude measurements in digital oscilloscope mode.

– Reference memories and non-volatile storage of all waveforms.

– Optional interface facilities for remote control and hard copy output.

– Storage of 64 front settings.

Upon receiving your PHILIPS PM3375, perform an initial inspection. Check the contents of the shipment for completeness and note whether any damage has occurred during transport. If the contents are incomplete, or if there is damage, a claim should be filed with the carrier immediately. The Philips/Fluke Sales or Service organization should be notified to facilitate the repair or replacement of the instrument.

The following parts should be included in the shipment of your PHILIPS PM3375:

– 1 Oscilloscope

– 2 Batteries

– 1 Front Cover (for PM3365A/PM3375 only)

– 1 Operation Guide or Bedienungsanleitung or Notice d’Utilisation

– 1 Mains Voltage Cord

– 2 Probes

– 1 Spare Fuse, 1.6 AT (located inside fuse holder)

– 1 Reference Manual

FRONT PANEL CONNECTORS

– CAL: Amplitude calibrated output socket.

– ⊥ (Ground): Measuring earth (ground) socket (banana).

– A: BNC input socket for channel A with probe indication.

– EXT: BNC input socket for channel EXTERNAL.

– B: BNC input socket for channel B with probe indication.

REAR PANEL CONNECTORS

– Z-MOD: BNC input socket for Z-modulation of the CRT trace.

– ANALOG PLOT OUT: Plot output socket to connect the oscilloscope to an analog XY plotter.

– LINE IN: Mains (line) input socket including fuse holder.

OPTIONAL REAR PANEL CONNECTORS

– IEEE BUS OPTION: Input/output socket to connect the oscilloscope to an IEEE 488/IEC 625 interface.

– RS232 BUS OPTION: Input/output socket to connect the oscilloscope to an RS-232C/V24 interface.

Before any connection to the inputs is made, the instrument must be connected to protective earth (ground) via the three-core mains (line) cable. The mains plug must be inserted only into a socket outlet provided with a protective earth (ground) contact. The protective action must not be negated by the use of an extension cord without a protective conductor. Any interruption of the protective conductor inside or outside the instrument is likely to make the instrument dangerous. Intentional interruption is prohibited.

The instrument has a tapless switched-mode power supply that covers most nominal voltage ranges from 100 V to 240 V (r.m.s.) at a frequency range of 50 Hz to 400 Hz. Always ensure the instrument is disconnected from all voltage sources when renewing a fuse. The mains (line) fuse rating is 1.6 AT delayed-action, 250 V.

The memory back-up batteries (2 * LR6 Alkaline Penlight) are not factory installed and must be fitted at delivery. Placement and replacement must be carried out by a qualified technician. To replace the batteries:

1. The instrument must be disconnected from the mains (line).

2. Remove the screw that holds the top cover at the rear of the instrument.

3. Gently push the cover backwards until it can be lifted.

4. Remove the cover by lifting it clear of the instrument. The memory battery back-up unit is now accessible, located on the instrument’s rear panel.

5. Ease off the clip that holds the memory back up unit to the chassis.

6. Gently slide the battery holder out of the chassis.

7. Install both batteries in their holders. The installation direction of the batteries is shown on the battery holder.

NOTE: When replacing the memory back-up unit, take care not to damage the wiring in the vicinity of the battery holder.

By pulling both handle ends outwards away from the instrument, the handle can be rotated to allow for the following instrument positions:

– Vertically on its rear feet.

– Horizontally on its bottom feet.

– In two sloping positions on the handle.

ATTENTION: Do not position the oscilloscope on any surface which radiates heat, or in direct sunlight. Ensure that the ventilation holes at the rear and top are free from obstruction.

Follow these steps for a quick start:

1. Connect the oscilloscope to the mains (line) voltage.

2. Switch the oscilloscope on by means of the push-button POWER LINE ON.

3. Adjust the TRACE ROTATION by means of a screwdriver so that the trace is parallel with the horizontal graticule lines.

4. Connect a probe to input A of the oscilloscope.

5. Connect the other end of the probe to the CAL output of the oscilloscope.

6. Press the AUTO SET key.

The AUTO SET function will automatically set all relevant parameters of the oscilloscope (attenuator setting, time base setting and trigger source setting) for an optimum trace. If you use an attenuator probe (10:1 or 100:1), it may be necessary to adjust it for correct compensation according to the instructions in the probe manual.

The front panel is designed with optimum ergonomic and logical lay-out of the controls, from left to right and from top to bottom. For ease of access, the front panel is divided into seven main areas:

– Screen controls

– Viewing area (screen + LCD)

– Up-down keys

– Function keys

– Rotary knobs

– Softkeys

– Inputs and outputs

After switching on the oscilloscope with the POWER LINE ON push button, the screen controls can be adjusted for optimum illumination, trace and spot quality.

– The trace and text intensity is set by the INTENS rotary knob.

– A sharp display is obtained by the FOCUS rotary knob.

– The screw driver control TRACE ROTATION is used to set a grounded trace parallel with the horizontal graticule lines.

– The graticule of the screen can be lit-up by the ILLUMINATION rotary knob, which can be useful in dark environments or for making photographs.

The viewing area consists of the screen of the Cathode Ray Tube (CRT) and a Liquid Crystal Display (LCD).

CRT Screen: The CRT screen is divided into a 10 * 8 divisions area. Each division contains five sub-divisions. On the left side of the CRT screen, four lines are marked with the values 100%, 90%, 10% and 0%. These marked lines can be used for percentage measurements or rise time measurements.

LCD Display: The LCD indicates all the selected active functions, settings and parameters. Its layout is logically divided into areas according to the keys and knobs. A flashing segment indicates a situation that requires your special attention, for example:

– An incorrect selection of knobs/keys controls.

– A VAR rotary knob in uncal position.

– The end of a UP-DOWN control range.

– A key has been operated during the PLOT action.

– The DISPL PART UP-DOWN key has been pressed in TB MAGN *1 mode.

– Display of register only.

The UP-DOWN keys select the required setting out of a range of settings possible for that function. They are used for the attenuator setting, the time base setting, the trigger delay setting and the display part setting.

The rotary knobs allow for continuously variable adjustment of the function that is obtained. The following rotary knobs are available:

– Y POS (A/B): Vertical screen position for channel A and B.

– VAR A/B: Variable attenuation for channel A and B. It is in the CALibrated position when fully clockwise.

– X POS: Horizontal screen position for the time-base.

– VAR (Time-base): Variable time-base adjustment (not used in DIGITAL MEMORY). It is in the CALibrated position when fully clockwise.

– TRIG LEVEL: Sets the trigger level.

– HOLD OFF: Adjusts the hold off time. It is in the normal position (minimum HOLD OFF) when fully clockwise.

The five softkeys located below the CRT are used for different functions in digital memory mode, such as AMPLITUDE CALCULATIONS, TIME CALCULATIONS, PROCESS MEASUREMENTS, choice of REGISTER MEMORY and the ZOOM facility. All calculation and manipulation facilities are activated via successive steps through the softkey menu structure.

When a menu is activated, the CRT screen contains two areas for text. The top text area shows all calculation information and channel settings, and the bottom text area shows all functions assigned to the five softkeys. The general softkey menu structure is as follows:

MAIN – MENU:

– CURSORS: Enters cursor control menu.

– SETTINGS: Displays active settings.

– PROCESS: Enters AVERAGE or ENVELOPE menu.

– MEMORY: Enters memory management menu for FRONTS, REGISTERS, and SHIFT.

– TEXT..OFF: Toggles the text display on the screen.

From these main menus, you can access sub-menus:

– From CURSORS, you can access CONTROL, CALC, ZOOM.

– From CALC, you can access AMPLITUDE and TIME calculation menus.

– From MEMORY, you can access FRONTS, REGISTERS, and SHIFT menus.

The RETURN softkey will always take you back to the previous menu level.

First, ensure the oscilloscope is operating in the analog mode (DIGITAL MEMORY indication in LCD is off). If it’s on, press the DIGITAL MEMORY key to turn it off. By pressing the AUTO SET key, the oscilloscope will automatically set the main functions to a clear optimal setting. Further adjustments and selections can then be made by operating the various keys and knobs.

To use the instrument as an analog oscilloscope, three main functions need to be defined:

– Vertical mode

– Horizontal mode

– Trigger mode

In analog vertical mode, you can make the following adjustments:

– Vertical display mode selection: Press the A/B key to select the channel you want to see (A, B, or A and B simultaneously). If the ADD function is in use, it is possible to switch off the channels A and B.

– Adjustment of the absolute zero level: Use the GND key and the Y POS rotary knob to position the zero level anywhere on the screen. Pressing the GND key interrupts the input signal and grounds the input signal path. Pressing it again reconnects the input. This is necessary for all DC measurements.

– Channel coupling: Use the AC/DC key. In AC position, the DC component of the signal is rejected. In DC position, the full bandwidth is available. AC coupling is used when a small AC signal has to be measured that is superimposed on a large DC voltage.

– Vertical amplitude adjustment: Operate the V…mV UP-DOWN key for the best setting. The range is from 2 mV up to 10 V per division in a fixed 1-2-5 sequence.

– Vertical variable attenuation: Adjust the VAR rotary knob. The UNCAL position is used when a measurement is taken in percentages. The UNCAL indication “>” flashes in the LCD. With the rotary knob, the measured signal can be set to 100%.

– Selection of ALTERNATED or CHOPPED display: Press the ALT/CHOP key when two signals are displayed. In alternate mode, the CRT beam alternately traces one signal sweep and then the other. In chop mode, the beam chops from one signal to the other at a fast switching frequency.

– Selection of ADD, NORMAL or INVERTED display: Press the ADD/INVERT key. “INVERT” is active on channel B. In ADD mode, channel B is added to channel A (A + B). In the ADD INVERT mode, channel B is subtracted from channel A (A-B). The differential mode (A-B) is useful for rejecting common-mode signals.

In analog horizontal mode, you can make the following selections:

– Selection of X deflection or horizontal time-base: Press the X DEFL key. In X deflection mode, the oscilloscope shows one signal displayed as a function of another signal (X-Y graph). The required X-axis signal is selected by the TRIG OR X SOURCE key (A, B, EXT or LINE).

– Selection of horizontal time scale: In horizontal time-base mode, use the TB s…µs UP-DOWN key to select the time coefficient in a 1-2-5 sequence. The VAR rotary knob allows for fine adjustments. The X MAGN key can expand the time-base 10 times. The X POS rotary knob shifts the trace across the screen in horizontal direction.

In trigger mode, the following selections can be made:

– Time-base trigger mode: Use the TB TRIG MODE key to select between AUTO, TRIG, or SINGLE mode.

– Trigger source selection: Press the TRIG OR X SOURCE key to select between channel A, A B (composite), channel B, EXT (EXTERNAL), or LINE.

– Trigger level: Adjust the TRIG LEVEL rotary knob to set the voltage level on the signal where triggering occurs.

– Trigger coupling: Use the TRIG COUPL key to select one of six modes: P-P (Peak-to-peak), DC, TVF (TV frame), TVL (TV line), LF (low-frequency reject), HF (high-frequency reject).

– Trigger slope selection: Press the slope key (symbol with rising/falling edge) to trigger on a positive-going or negative-going slope.

– Hold-off time: Use the HOLD OFF rotary knob to prevent “false” triggering on complex signals by inhibiting the trigger for a period of time after a sweep is completed.

First, ensure the oscilloscope is operating in the digital mode by pressing the DIGITAL MEMORY key (the DIGITAL MEMORY indication in the LCD will be on). By pressing the AUTO SET key, the oscilloscope will automatically set the main functions to the most convenient setting.

Further adjustments can be made by operating the keys. In DIGITAL MEMORY mode, there are more functions available than in analog mode. The analog functions that are not available are ADD, ALT/CHOP, COMP TRIG, X VAR. This section will describe the functions unique to digital operation.

Three main functions should be defined:

– Vertical mode

– Horizontal mode

– Trigger mode

In digital vertical mode, the following additional choices can be made:

– Dotted or joined display: Pressing the DOTS key toggles the display. In digital memory mode, the traces are built-up by “dots” of samples. You can select a “dotted” display or an interpolated (dotjoined) display where the dots are interconnected by a line for a continuous appearance.

– Loading of register memory: Press the LOAD key. The oscilloscope has a display memory and three register memories (R1, R2, R3) for storing reference waveforms. To store a waveform, select a destination register (R1, R2, or R3) using the softkeys MEMORY and REGISTERS, then press the LOAD key. The waveforms are stored even after power down if a battery back-up is equipped.

– Display of register memory: Press the DISPLay key. Pressing it once shows the contents of the display memory and the selected register memory together. A second press shows only the selected register memory. A third press returns to displaying only the display memory.

– Status of register memory: Press the STATUS key. Pressing it once enables the LCD to show the full settings of the selected register memory. Pressing it twice within one second shows the complete settings of the display memory (R0).

In digital horizontal mode, you select the time scale with the TB s…µs UP-DOWN key. The digital time-base has three modes:

– ROLL (PM3350A/55/65A/75): 50 s/div … 1 s/div. The screen build-up is from right to left.

– RECURRENT (PM3350A/65A/3355/75): 0.5 s/div … 0.5 µs/div for 50A/65A, and 0.5 s/div … 0.2 µs/div for 3355/75. The screen build-up is from left to right.

– SAMPLING (PM3365A/75 only): 0.2 µs/div … 20 ns/div for PM3365A, and 0.1 µs/div … 20 ns/div for PM3375. Repetitive signals are needed for screen build-up from left to right.

You can use the X MAGN key for horizontal magnification of 2, 4, 8, 16, or 32 times. The DISPL PART UP-DOWN key allows you to select which part of the magnified signal is displayed. The LCD bar shows the position of the displayed part relative to the memory length.

In DIGITAL trigger mode, the following extra functions are available:

– SINGLE SHOT: Activated by pressing the TB TRIG MODE key and the RESET key. In DIGITAL MEMORY mode, the display memory content is refreshed once after a suitable trigger is received. This mode is very useful to capture a signal that occurs only once. After operation, the time-base is ARMED and waits for a trigger.

– MULTIPLE SHOT: Activated by pressing the TB TRIG MODE key and the RESET key. The contents of the selected register memory are refreshed ONCE after the FIRST trigger, and the display memory contents are refreshed ONCE after the SECOND trigger is received. The time base is ARMED and waits for TWO new triggers.

– TRIGGER DELAY SETTING: Use the TRIG DEL UP-DOWN key. This offers PRE- and POST-triggering. In PRE-triggering, you can look BEFORE the trigger point (e.g., delay = -10 divisions). In POST-triggering, you can look AFTER the trigger point (e.g., delay = +10 divisions). This effectively stretches the memory capacity.

Amplitude measurements are performed using the cursors in DIGITAL MODE.

– Vpp (Peak-to-peak voltage): The Vpp amplitude measurement is calculated over the signal lying between the MAIN CURSORS. Activate the Vpp calculation function, and the oscilloscope will automatically measure the peak-to-peak voltage and show the measuring points with two small LOCATE CURSORS.

– ABS (Absolute voltage): This measurement is calculated from the MAIN CURSORS related to the absolute zero level (ground). To use this function: activate ABS, ground the trace and adjust the zero level with Y POS, then press the GND key again. Do not re-adjust the Y POS knob.

– RMS (Root mean square voltage): This measurement is calculated between the MAIN CURSORS and related to the absolute zero level. The procedure is the same as for ABS: activate RMS, ground the trace to set the zero level, then un-ground it. Do not re-adjust the Y POS knob.

– MEAN (Mean voltage): This measurement is calculated between the MAIN CURSORS and related to the absolute zero level. The procedure is the same as for ABS and RMS.

The results for all measurements are shown in the top text area of the screen. If the VAR knob is in CAL position, the result is in Volts; if in UNCAL position, the result is in Divisions.

Time measurements are performed using the cursors in DIGITAL MODE.

– FREQ (Frequency): The FREQ measurement is calculated between the MAIN CURSORS. Activating the function will automatically measure the period time and show the measuring points with two small LOCATE CURSORS. Minimal one signal period should be covered by the MAIN CURSORS.

– PERIOD: The PERIOD measurement is calculated between the MAIN CURSORS. Activating the function automatically measures the period time and shows the measuring points. Minimal one signal period should be covered.

– WIDTH (Pulse width): The WIDTH measurement is calculated between the MAIN CURSORS. The pulse width is determined on the half peak-to-peak amplitude between the MAIN CURSORS. There must be at least one upgoing and one downgoing edge between the cursors.

– RISE (Rise-time): The RISE (or FALL) measurement is calculated between the MAIN CURSORS. The rise-time is determined on the nearest sample to the 10% and 90% level of the amplitude between the MAIN CURSORS.

The results are shown in the right corner of the top text area on the screen.

The ZOOM and AUTO ZOOM functions are used to magnify a part of a signal while retaining full sample resolution over the selected part.

ZOOM: If part of the signal needs to be examined in more detail, the ZOOM function can be used. The main cursors can be set on the wanted trace and on the signal part of interest. Then, by entering the ZOOM menu and activating the RESTART function, a new acquisition will be made in the adapted time base and delay setting. This means that the selected part is resampled using full memory and at a higher sample rate. The REVERSE function resamples at the previous settings. The CENTER function sets the main cursors horizontally to +2 DIV and -2 DIV from the screen center.

AUTO ZOOM: This mode simulates a delay time-base function by displaying a main time-base signal and a delayed time-base signal together. The main time-base signal is stored in one of the register memories. When AUTO ZOOM is activated, the MAIN CURSORS are set on the stored signal and the LOCATE CURSORS are on the live signal. These cursors indicate the part of the signal that is displayed in more detail. When the distance between the LOCATE CURSORS is less than 3 divisions or more than 9 divisions, then the time-base is automatically set to a more suitable setting.

The register memories R1, R2 and R3 make it possible to store different waveforms in the oscilloscope memory. These signals remain stored after power down and can be displayed on screen whenever needed for signal comparison.

1. First, select one of the register memories with the REGISTERS menu. This menu is entered by pressing the MEMORY softkey and then pressing the REGISTERS softkey.

2. Now load a reference signal into the selected register memory by pressing the LOAD key. This way all three register memories can be selected and filled with reference signals.

3. Now a measured (“live”) signal (R0) can be compared with one of the stored reference signals by displaying the signals on screen simultaneously.

The measured signal can be moved on the screen by means of the Y POS rotary knob. But when the instrument is in the LOCK-mode, the measured signal and the stored signal can be moved on the screen by using the SHIFT function (see MEMORY menu).

This mode is possible for all versions of the oscilloscope. To set up for an analog plot:

1. Enter the service menu by pressing the MENU key and keeping it pressed. Now also press the AUTO SET key and * becomes visible in the LCD.

2. Press softkey APPL to enter the application preselect menu.

3. Press softkey PLOT.

4. If present, press softkey PLOT-KEY until “plot analog” appears in the top text area of the CRT. This has the result that the analog plot action is started if the front panel key PLOT is pressed.

5. Press softkey PLOT-A: this gives access to the set up menu for the analog plot mode. Via this menu the PLOTSPEED (range 20 … 2000 ms/dot) for slow-rate limitations and the PENLIFT (#, pen on paper at high or low level) can be adapted to the plotter. Moreover with GRID on, a graticule is plotted.

6. Press front panel key AUTO SET in order to leave the service menu.

To start plotting, press the front panel PLOT key.

The Application Preselect Menu allows you to select functions that do not need to be entered frequently. Proceed as follows to enter the menu:

1. Press MENU and keep it pressed. Now also press AUTO SET.

2. Now the Service menu has been entered, the LCD should indicate “* * *”.

3. Press APPL, which is one of the CRT softkeys.

4. The CRT should indicate “APPLICATION PRESELECT MENU” on the upper side of the screen.

The selections are made with the softkeys under the CRT. The selected functions are displayed in the top text line of the CRT. Available selections include:

– PLOTTER PARAMETERS (PLOT): Enters menus for setting up analog plot, digital plot, or printer parameters.

– SINGLE SHOT (SNGL_SHOT): In analog single shot mode, define if the shot is always on channel A (FIRST) or alternates between A, B and ADD (MULTI).

– TV TRIGGERING AFTER AUTOSET (AUTO): Select the TV trigger mode (TVFrame or TVLine) that the oscilloscope should use after an AUTOSET command.

– IEEE-488: OPTIONAL (IEEE): Define the IEEE mode and address if the option is present.

– RS-232C: OPTIONAL (RS232): Define RS-232C parameters like speed, parity, stop bit, and data bit if the option is present.