DATEL DMS-40PC Series handbook
Contents
1. DIGIT LED DISPLAY DIGITAL PANEL VOLTMETERS Performance Functional Specifications Typical at Ta 25 C and supply voltage 5V using the single ended input circuit unless otherwise noted Order on line at www datel com Analog Inputs Min Typ Max Units Full Scale Input Range DMS 40PC 1 2 Volts DMS 40PC 2 20 Volts DMS 40PC 3 200 Volts Input Impedance DMS 40PC 1 100 1000 MQ DMS 40PC 2 3 0 8 1 MQ Overvoltage Protection 250 Volts Common Mode Voltage Range 2 Volts CMRR dc to 60Hz 86 dB Control Inputs Decimal Point Placement Pins 4 6 8 Tie to pin 3 to activate Display Test Pin 2 Tie to pin 3 to acti vate all segments Display Hold Pin 9 BCD Outputs Tie to pin 3 toh old last reading Ordering Information DMS 40PC 1 RS LED Color GS Standard Green Input Range RH High Intensity Red 1 2V RL Low Power Red 2 20V RS Standard Red 3 200V YS Standard Yellow BCD Output Models BCD outputs are only available on standard red meters DMS 40PC 1 RS BCD for 2V input range DMS 40PC 2 RS BCD for 20V input range DMS 40PC 3 RS BCD for 200V input range DMS 40PC 1 RL BCD for 2V input range DMS 40PC 2 RL BCD for 20V input range DMS 40PC 3 RL BCD for 200V input range Accessories DMS PS1 CM 5V 1 0A AC DC power supply module DMS 30 CP Panel cutout punch DMS BZL1 DMS 40 bezel assembly DMS BZL2 DMS 40 bezel assembly with seal2. More importantly while the signal across R3 is single ended both ends of R1 and R2 are well above ground and are described here as being differential Please note that while the DMS 40PC can measure the voltages across either R2 or R3 it cannot measure the 1 6666 volts across R1 The voltage at the lower end of R1 is approximately 3 333V and this exceeds the common mode voltage limit of 2V DMS 40PC 1 GS m R1 DPI 5V SUP DATEL 85 264Vac DMS PS1 CM AC to DC Converter Figure 3 Differential Input Configuration 3 Power Supply Monitoring One of the most widely used digital panel voltmeter applications is monitoring the output voltage of a system power supply often the same supply that also powers the meter The low power red LED DMS 40PC 2 RL with its excellent 0 001Vdc resolution can be configured to monitor power supplies with outputs in the range of 4 5 18Vdc The circuit in Figure 4 uses a low drop out three terminal regulator LM 2931T 5 in a T0 220 package available from National Semiconductor to provide regulated 5V power to the meter The LM 2931 was chosen because it has the following on chip protection features reverse polarity short circuit and thermal runaway The DMS 40PC 3 RL can monitor voltages up to 200Vdc provided a separate 5V power source is used since many three terminal regulators cannot operate with supply voltages greater than 24V Red low p
3. 0 0 DMS 40PC 0 0 Purchase On Line EE www datel com COCCI CIC Pd Actual Size D OATEL INNOVATION and EXCELLENCE DMS 40PC Series 42 Digit LED Display Precision Miniature Digital Panel Voltmeters Features DMS 40PC Series 4 Digit LED Display Miniature DPM s are fully self contained e Precision autozeroing factory calibrated A D converter component like plug in meters that provide scientific grade accuracy typically 2 counts or 0 005 of full scale and outstanding reliability at a very affordable price Within its miniature 2 17 x 0 92 x 0 56 epoxy encapsulated package each e Scientific grade accuracy 2 counts meter contains a precision reference circuit a high resolution autozeroing factory Miniature size calibrated A D converter and a large 0 52 13 2mm easy to read LED display 2 17 x 0 92 x 0 56 LED s are available in red yellow and green colors Red LED s are also offered in 55mm x 23mm x 14mm e Large 0 52 13 2mm LED display Choice of red green or yellow colors e High intensity or low power red high intensity or low power versions The versatile design of the DMS 40PC Series assures trouble free installation and long term operation Differential input voltage ranges include 2V 20V and 200V Input impedance is a minimum 800k Non inverting inputs are overvoltage protected to 250V and CMRR is typically 86dB dc to 60Hz LED s optional The DMS 40P
4. C s epoxy encapsulated package has an integral bezel and color e Single 5V supply 175mW for low filter The moisture and vibration proof package is extremely rugged and well suited for power models harsh environments and extended temperatures Devices are fully specified for e Epoxy encapsulated 12 pin DIP with 0 to 50 C operation built in color filter and bezel e 3 differential input voltage ranges e DISPLAY HOLD and TEST functions e Optional BCD data outputs for CPU displays interface e 0 to 50 C temperature range All models operate from a single 5V supply and typically consume 500mW Low power models whose display is just as bright as standard models typically consume 175mW DISPLAY TEST and HOLD functions are standard on each meter and a complete set of BCD outputs are optional for sending data to CPU s or remote po 5V 1 5V SUPPLY 12 O INPUTLO DISPLAY TEST DC DC CONVERTER 5V RETURN A D CONVERTER DATA 11 INPUT HI 909k 1o ANALOG COMMON 9 O DISPLAY HOLD PPP Le O REFERENCE IN OUT R2 is not used on 2V 1 models R2 101k on 20V 2 models and 9 2k on 200V 3 models Figure 1 DMS 40PC Series Simplified Schematic DATEL Inc Mansfield MA 02048 USA e Tel 508 339 3000 800 233 2765 Fax 508 339 6356 e Email sales datel com e Internet www datel com DMS 40PC 4
5. LED DISPLAY DIGITAL PANEL VOLTMETERS Mechanical Specifications MECHANICAL DIMENSIONS Inches mm TOLERANCES 2 PL DEC 0 02 0 51 3 PL DEC 40 010 0 254 PINGH v a LEAD DIMENSIONS 0 025 0 635 x 0 025 0 635 NOMINAL IDENTIFIER RECOMMENDED PC BOARD FINISHED HOLE DIAMETER Venni 7 Svol a 0 042 0 003 1 067 0 076 CALIBRATION POTENTIOMETER HOLE LOCATION INSIDE ROW BCD MODELS ONLY FRONT VIEW INSIDE ROW BCD MODELS ONLY PIN 1 LSD DIGITS A 5V SUPPLY 1 INPUT LO L B4 MSD DIGIT 1 B DISPLAY TEST 2 INPUT HI K B2 DIGIT2 C 5V RETURN 3 ANALOG COMMON J B1 LSB DIGIT3 D DP3 4 DISPLAY HOLD B8 MSB DIGIT4 E DP2 5 DP4 H STROBE POLARITY F DPI 6 REFERENCE IN OUT G BUSY DP1 DP2 DP3 DP4 0 125 3 175 DIAMETER sis ai USE ONLY WHEN PC BOARD MOUNTING osa I en 0 84 2 09 21 3 D 53 1 0 560 14 22 0 25 6 4 TYP 0 040 allal BCD MODELS ONLY 1 02 0 10 1 60 0 10 e a 2 5 Tapi 40 6 2 5 TYP 0 17 TYP 1 80 0 15 43 45 7 I 3 7 Typ i 0 50 0 040 12 7 gt 1 02 OPTIONAL BEZEL DMS BZL1 and DMS BZL2 BEZEL INSTALLATION 0 187 2 56 INSERT 4 75 FRONT VIEW 0 156 3 96 DEEP PANEL YSN NI Sav b S gt j BEZEL E 2 55 64 77 Sc RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS 0 116 INTERNAL CORNER RADII 2 95 e 0 032 0 81 MAX a TT RETAINI
6. NG CLIP INSTALLATION 1 07 0 878 in 27 18 PANEL CUTOUT 22 30 i Job z l l l PANEL l l v l d l 2 118 53 80 I C sS 2 35 59 69 i 0 096 0 093 2 362 DIAMETER 4 REQUIRED 2 44 ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY D OATEL INNOVATION and EXCELLENCE DATEL Inc 11 Cabot Boulevard Mansfield MA 02048 1151 Tel 508 339 3000 800 233 2765 Internet www datel com Email sales datel com DATEL makes no representation that the use of its products in the circuits described herein or the use of other technical information contained herein will not infringe upon existing or future patent rights The descriptions contained herein Fax 508 339 6356 ISO 9001 REGi S TERED DATEL UK LTD Tadley England Tel 01256 880444 DATEL GmbH Munchen Germany Tel 89 544334 0 DATEL KK Tokyo Japan Tel 3 3779 1031 Osaka Tel 6 354 2025 do not imply the granting of licenses to make use or sell equipment constructed in accordance therewith Specifications are subject to change without notice The DATEL logo is a registered DATEL Inc trademark DS 0272C 1 98 DATEL S A R L Montigny Le Bretonneux France Tel 01 34 60 01 01
7. erminals at the same potential as the DMS 40PC s 5V RETURN pin 3 Single ended inputs are usually derived from power supplies that have a common ground with the meter s 5V supply Figure 2 shows the recommended connections to be used with this type of input Pin 12 INPUT LO is shown directly tied to ground This connection to ground must be a separate wire or pc board trace originating at Vin s negative terminal This hook up will normally eliminate display instabilities and errors caused by ground loop currents which can occur if INPUT LO is tied to ground at or near pin 3 DMS 40PC 1 GS 11 IN HI DATEL 85 264Vac DMS PS1 CM AC to DC Converter Figure 2 Single Ended Input Configuration DMS 40PC 4 DIGIT LED DISPLAY DIGITAL PANEL VOLTMETERS Applications 2 Differential Input Configurations Differential inputs can also be measured with DMS 40PC meters as shown in the circuit of Figure 3 Differential inputs must also originate from power supplies that have a common ground with the meter s 5V RETURN pin 3 However differential inputs usually have both terminals above and or below 5V RETURN Figure 3 though not necessarily a typical real world application does serve the purpose of illustrating the concept of a differential signal The voltages developed across R1 R2 and R3 are equal to each other and measure approximately 1 6666Vdc or 1 3 of the 5V power source
8. gital A D conversion cycle and remains high until the conversion ends STROBE pin H A string of five sequential active low STROBE pulses are output after BUSY goes low indicating the end of a conversion and the availability of new data The 5 STROBE pulses occur only once per conversion or 2 5 times each second STROBE can be used to latch the BCD data on pins L into external latches Either edge can be used since STROBE 5ysec wide is active only in the center of the corresponding DIGIT DRIVE and BCD DATA outputs POLARITY pin F This pin which is also used inside the DMS 40PC to drive the negative sign segment indicates whether the last input signal conversion was positive POLARITY set high or negative POLARITY set low POLARITY unlike BCD DATA is not multiplexed For data latching purposes POLARITY should be sampled during the STROBE pulse for digit 1 most significant digit Ba Approx 8msec Approx 2msec gt k DIGIT DRIVE 1 re MSD Approx 2msec gt lt _ DIGIT DRIVE 2 i EO OO DIGIT DRIVE 3 i L DIGIT DRIVE 4 o O e a DIGIT DRIVE 5 LSD BUSY a a A Approx 5usec Ix STROBE OUT Data from pe Previous Conversion BCD DATA 4 LINES fi 5 Strobes Only Per Conversion f 1 2 MSD 3 T T T T 1 2 3 4 5 T 4 5 LSD Figure 6 BCD Data Timing Diagram DMS 40PC 4 DIGIT
9. hould not exceed the supply voltage See Technical Notes BCD outputs are optional and must be specified in the part number See Ordering Information Includes high intensity and BCD output models Technical Notes 1 ANALOG COMMON Pin 10 This pin is an internal low noise ground for the DMS 40PC It is internally connected to pin 3 5V RETURN Do not connect pin 10 to either pin 3 or your system ground as this will create a ground loop and possibly result in erroneous readings REFERENCE INPUT OUTPUT Pin 7 This pin accesses the meter s internal reference and is used during the factory calibration procedure Pin 7 should be left open in most common applications It can be used in certain ratiometric applications in which it is desirable for the meter s reference to track an external reference See Ap Note 3 in the DATEL Panel Meter Catalog for more details DISPLAY TEST Pin 2 Connecting pin 2 to ground pin 3 5V RETURN will activate all LED segments and the display will read 18888 regardless of the actual applied input To reduce self heating the display should not be left in the test mode for more than 10 seconds This pin should be left open if unused DISPLAY HOLD Pin 9 For normal operation this pin should be left open To hold the meter s last reading and display it continu ously tie pin 9 to ground pin 3 5V RETURN Decimal Point Placement The location of the decimal p
10. ing gasket DMS EB Application evaluation board with standard MOLEX connector decimal point solder pads and attenuation resistor pads A panel mount retaining clip is supplied with each model Display Display Type and Size Logic levels 1 LSTTL load max Logic 1 2 4 Volts Logic 0 0 4 0 8 Volts Performance Sampling Rate 2 5 samples per second Accuracy 15 minute warm up DMS 40PC 1 Vin 1 9V 2 3 Counts DMS 40PC 2 Vin 19V 3 4 Counts DMS 40PC 3 Vin 190V 3 4 Counts Zero Reading Vin 0 Volts 0001 0000 0001 Temperature Drift 0 to 50 C DMS 40PC 1 0 4 1 Cnts C DMS 40PC 2 3 0 4 41 5 Cnts C Power Supply Requirements Supply Voltage 4 75 5 00 5 25 Volts Supply Current Standard Models 100 140 mA Low Power Models 35 50 mA 4 Digit LED 0 52 13 2mm high Polarity Indication Autopolarity for negative Vin Overrange Indication Physical Environmental 0000 flashing for negative Vin 0000 flashing for positive Vin Operating Temperature 0 50 C Storage Temperature 20 75 C Humidity Non condensing 0 95 Case Material Polycarbonate Weight 0 75 ounces 21 grams Applies for transient or continuous overvoltages applied to INPUT HI pin 11 with INPUT LO pin 12 properly connected Pin 12 is not overvoltage protected see Figure 1 Voltages applied to pin 12 s
11. ious section 11 DMS 40PC 1 GS INH 1 3 5V SUP 5V RET AC to DC Converter z i 10 asv l ANA COMM CELL T 12 IN LO al Jo DATEL 85 264Vac DMS PS1 CM Figure 5 Floating Input Measurements 4 DIGIT LED DISPLAY DIGITAL PANEL VOLTMETERS DMS 40PC Applications 5 Engineering Scaling and Input Attenuation In many applications the input signal must be scaled or divided down before being applied to the DMS 40PC In some situations the input signal exceeds the full scale range of the meter and in other applications a direct one to one relation does not exist between the input voltage and the desired display reading For an example of the second situation assume an input voltage of 1 0Vdc is required to display a reading of 7500 when applied to a 2V input meter An input divider circuit constructed with two series resistors with an output to input ratio of 0 75 will scale the 1 0V signal down to 0 75V Engineering scaling and input attenuation are discussed in Ap Note 4 of the DATEL Digital Panel Voltmeter Catalog Compen sating for inputs which have a zero offset is also discussed 6 BCD Outputs DMS 40PC X RS and RL BCD Models Only Models with a BCD suffix have 12 extra output pins labeled A through L 6 per side that provide the following information multiplexed serial BCD data digit drive and polarity indication The data present on pins A L si
12. multaneously drives the meter s internal LED display All functions on pins A L are 5V CMOS compatible however they are only rated to drive one 74LS series TTL load CMOS logic IC s for example 74HC or 74HCT series devices should be used when more fan out capability is required As the timing diagram in Figure 5 indicates 100Hz is the optimum display scan rate when the BCD outputs are used to drive external LED displays Faster scan rates while permissible are not necessary Slower scanning however may result in noticeable flickering of the display Common anode LED s combined with a 74LS247 BCD to seven segment decoder is the simplest way of implementing an external display A seventy five to one hundred Ohm resistor on each LS247 segment drive output provides adequate display brightness The functions of pins A L are listed below BCD DATA pins L Four lines are used for BCD Binary Coded Decimal data outputs representing the numbers 0 9 Positive logic convention a high represents a 1 is used DIGIT DRIVE pins A E These five outputs when gated with STROBE can be used to direct the BCD DATA into external latches DIGIT DRIVE outputs may also be connected directly to the bases of NPN transistors in remote display configurations The digits are scanned right to left i e MSD DIGIT 1 DRIVE to LSD DIGIT 5 DRIVE BUSY pin G This is a status pin that goes high at the start of an analog to di
13. oint is user selectable and the decimal point control pins DP1 DP4 are active low functions Select the appropriate decimal point by tying pin 4 5 6 or 8 to pin 3 5V RETURN Unused decimal point location pins should be left open 4 DIGIT LED DISPLAY DIGITAL PANEL VOLTMETERS DMS 40PC Hard wiring is preferable however you can exercise dynamic control over the location of the decimal point by employing drive circuits that are capable of sinking a minimum of 20mA at voltages less than 0 4 Volts 6 Gain Adjust There is a gain adjust potentiometer on the back of each meter It has approximately 150 counts of adjustment range Since these meters essentially have no zero offset errors a gain adjustment is effectively an overall accuracy adjustment Though they may be performed at any point except zero accuracy adjustments are most effective when performed with higher level input signals 7 Soldering Methods All models in the DMS 40PC Series easily withstand most common wave soldering operations We recommend however that you evaluate the effects your particular soldering techniques may have on the meter s plastic case and high precision electrical performance We recommend the use of water soluble solders and thorough cleaning procedures 8 Suggested Mating Connectors Panel mounted Connector housing DATEL P N 39 2079400 Terminal type DATEL P N 39 2099090 Crimping tool DATEL P N 39 2099000 Wire si
14. ower LED models with their very low self heating are recommended for applications in which low calibration drift is desirable When using other higher power DMS 40PC models in combination with three terminal regulators be sure to consult the regulator manufacturer s data sheet to ensure the device is being utilized safely and correctly INHI LM2931T 5 11 DMS 40PC 2 RL 1 5V SUP att 45 18Vde Figure 4 4 5 18V Power Supply Monitor 4 Floating Signal Source Measurements A floating input is a signal that before it is applied to the DMS 40PC s inputs has no galvanic connection direct current path to the meter or the meter s power supply The circuit shown in Figure 5 illustrates the necessary connections for measuring floating inputs The 1 5V battery represents a true floating input signal since it initially has no connection whatsoever in common with the meter Real world floating inputs typically originate from power supplies which are transformer isolated from the DMS 40PC s 5V supply The connection of pin 12 INPUT LO to pin 10 ANALOG COMMON is required in order to provide a bias return for the meter s input amplifier This is because neither pin 11 nor pin 12 are tied to any reference voltage inside the DMS 40PC see Figure 1 These connections are not made internally in order to give the meter the ability to make differential measurements as described in a prev
15. when debugging a malfunctioning circuit especially if the user has some knowledge of operational amplifiers op amps The meter s high impedance input consists of an op amp powered from a 5Vdc power supply the 5V is internally generated Figure 1 shows that input signals applied to INPUT LO and INPUT HI must to be kept within the 5V power supply rails Also note that only pin 11 has a current limiting 909kQ series resistor High input voltages that have a common ground connection with pin 3 5V RETURN should only be applied to pin 11 INPUT HI and never to pin 12 In these high voltage cases pin 12 should always be tied to pin 3 5V RETURN One of the simplified schematic s more noteworthy features is that it shows some DMS 40PC internal voltage values and also that pin 3 is the meter s zero volt reference point regardless of the type of power or signal source used This is an important point to keep in mind when using digital multimeters to perform system level measurements The multimeter s negative lead usually the black one must always be connected to pin 3 5V RETURN This is the only way accurate readings can be made particularly if the meter is configured for a differential input and concerns arise regarding common mode voltages 1 Single Ended Input Configurations The DMS 40PC can measure single ended signals with either positive or negative polarities True single ended inputs always have one of their two t
16. ze 22 to 26 AWG Insulation diameter 0 062 1 57mm maximum Stripping length 0 100 to 0 125 2 54 to 3 17mm Board mounted Socket DATEL P N 39 2359625 Applications DMS 40PC Series meters are high precision versatile devices that can be used in many applications requiring a 0 to 19 999 count digital display The application circuits chosen for this section are ones that have historically received many inquiries Every attempt has been made to ensure technical accuracy and all of the following circuits have been prototyped and tested to ensure functionality Please keep in mind however that real world applications are seldom as straightforward as the approaches presented here All inputs applied to DMS 40PC meters must be steady dc values otherwise the input itself may cause display instabilities Due to their 412 digit resolution DMS 40PC meters must be wired with greater care than their 3 2 digit counterparts Correct power supply and input signal wiring an absolute must helps eliminate ground loop induced errors that show up as unstable display readings When an input signal assumed to be exactly zero volts has a 1mV 0 001V ground loop induced offset it is displayed as 0010 ona 2V input range meter DATEL s new Digital Panel Meter Catalog contains an application note describing power supply wiring and ground loop avoidance techniques The DMS 40PC s simplified schematic shown in Figure 1 can be very useful
Download Pdf Manuals
Related Search
DATEL DMS 40PC Series handbook