DMS-40LCD-4/20S Series www.murata-ps.com Ultra-Low 2.9V Loop-Drop 4 Digit LCD Display Process Monitor The DMS-40LCD-4/20Ss ultra-low 2.9V typical loop-drop (190-Ohm burden) makes it FEATURES ideal for use in 4-20mA process monitoring applications which have two or more series- Loop-powered, no power supply required connected loop-monitoring devices. The low loop-burden means it can be used in current 2.9V typical loop-drop 190-Ohm (max.) loop loops that are powered from supply voltages as low as +8Vdc The DMS-40LCD-4/20S is impedance self-powered all required operating power is derived directly from the current loop itself. It requires no separate dc power supply or special grounding considerations and can be Dip-switch-selectable range, offset, and connected ANYWHERE in the loop decimal points The DMS-40LCD-4/20Ss input, span, and offset circuits all employ super-stable, 0.5% Hundreds of different input/readout combinations thin-lm chip resistors. Long-term stability and accuracy are assured by driving these tight- Non-interacting gain (span) and offset (zero) tolerance resistors with an ultra-stable, 0.2% band-gap voltage reference. Unlike many 20-turn potentiometers competitors designs, the two precision 20-turn span and zero adjust poten- tiometers Large, 0.40 (10.0mm) high, sunlight-viewable do not interact with one another. Its full-size, 0.40 (10.0mm) high-contrast 4 digit LCD LCD digits display offers 19,999 counts of resolution and can be read in virtually any lighting condi- Miniature size: 2.17 x 0.92 x 0.90 tionincluding full sunlight (55mm x 23mm x 23mm) All range-change and decimal point selections are made by conguring two gold-plat- Vibration-resistant package reliable screw- ed, vibration-resistant, six-position DIP switches. The two connections to the current loop terminal connections are made via a reliable, screw-type terminal block. To further enhance reliability, the design features 100% soldered connectionsno troublesome zebra/elastomercic connectors are 100% soldered connections used. All these outstanding features make the DMS-40LCD-4/20S the highest quality, most rugged, 4 digit, LCD-display process monitor available. 4 DIGIT A/D CONVERTER Range Offset Gain DATA DP1 DP2 DP3 DP4 R3 R7 ZERO GAIN ADJUST ADJUST BAND-GAP REFERENCE CIRCUIT ONON ONON S1 S2 1 2 3 4 6 11 2 3 4 55 6 111 22 33 44 55 66 +5V 5V TB1 + CURRENT TO DC/DC VOLTAGE CONVERTER CONVERTER 12 + 4-20mA For full details go to Current Loop Input www.murata-ps.com/rohs Figure 1. DMS-40LCD-4/20S Simplied Schematic www.murata-ps.com/support MPM DMS-40LCD-420.C01 Page 1 of 5DMS-40LCD-4/20S Series Ultra-Low 2.9V Loop-Drop 4 Digit Performance/Functional Speci cations LCD Display Process Monitor Typical at TA = +25C, unless otherwise noted. Consult Murata Power Solutions for more information regarding Current Loop Input Min. Typ. Max. Units display readings not shown in the table. Full Scale Input Range (1) +3.8 +20.4 mA (2) Max. Loop-Voltage Drop/Max. Loop impedance: The maximum Loop Burden(2) 190 Ohms loop voltage-drop and maximumloop impedance (burden) are both Voltage Drop (2) 2.9 3.8 Volts speci- ed with the meter congured for DIP-Switch setting 20 and Overcurrent Protection 40 mA an input loop current of 20.0mA. Performance (3) Temperature Drift: Temperature drift of zero and temperature drift of Sampling Rate 2.5 reading per second gain are both specied with the meter congured for range 20 with a 4mAinput adjusted (using R3) to read 0000 1 count, and a 20mA Accuracy (1 minute warm-up) 0.05%FS 1 Count input adjusted (using R7) to read 19000 2 counts at an initial Temperature Drift of Span(3) 0.3 0.6 Cnts/C ambi- ent temperature of 25C. Temperature Drift of Zero(3) 0.2 0.5 Cnts/C The temperature drift of gain is proportional to the selected full-scale Display range. It is typically less pronounced at the lower range settings, that DisplayType and Size 4digit, 0.4/10.2mmhigh LCD is, if the observed gain drift of a particular meter is +12 counts when Polarity Indication for negative readings reading 19000 on range 20 at 40C, the same meter will most likely have a drift of only +6 counts when reading 9000 on range 1 for negative inputs Overrange Indication 1 for positive inputs 12 at 40C. Physical/Environmental The normally very accurate, temperature-insensitive autozero feature of the DMS-40LCD-4/20Ss built-in analog-to-digital converter (A/D) OperatingTemperature 0 +50 C is not a signicant factor in determining the meters overall zero- StorageTemperature 20 +75 C reading stability over its rated operating temperature because an Humidity (non-condensing) 0 95 C offset voltage is applied to the A/Ds LOinput. This offset is used to Case Material Polycarbonate null the signal voltage developed with a 4mAinput. In order for the A/ Weight 0.1 ounces (28 grams) Dto display a steady 0000 1 digit, the autozero circuitry requires both A/Dinputs to always be at exactly zero volts. The meters zero-reading stability over its specied operating temper- Ordering Information ature is affected by the drift of three terms: the voltage developed by the meters offset circuitry the voltage developed across the meters DMS-40LCD-4/20S-C 4 digit, LCD, loop-powered meter input resistors with a 4mAinput and the stability of the applied DMS-BZL1-C Panel-mount bezel assembly 4mAinput signal itself. In the lower DIP-switch settings (ranges 1-4), DMS-BZL2-C Panel-mount bezel assembly with the meters parasitic etch and switchimpedances also contribute a sealing gasket small error voltage. DMS-30-CP Panel cutout punch The meters performance with regards to span stability over tem- A panel-mount retaining clip is supplied with each meter. perature is affected by the drift of the meters gain circuitry and loop input-resistors. To minimize these drifts in applications requiring the utmost in temperature stability, where possible, the meter should be TECHNICAL NOTES calibrated at its anticipated operating temperature. (1) Full Scale Input: The Display readings shown in Table 1 can typi- Since the DMS-40LCD-4/20S uses extremely-stable thin-lmchip cally be obtained with transmitters having a low-level output of 3.8 resistors, periodic re-calibration is typically required only in envi- to 4.3mA and a full-scale output of 19.4 to 20.4mA. When using a ronmentally demanding applications where shock, vibration, and/or transmitter whose output falls outside these ranges and the desired temperature extremes may have a detrimental effect on the 20-turn display read- ings are close to the upper or lower adjustment limits potentiometers. of the selected DIP-switch setting , try using the next highest DIP- switch setting if, after adjusting R7, the display reading is still too DECIMAL POINT SETTINGS low, or the next lowest setting if the display reading is still too high Using the chart below as a guide, the DMS-40LCD-4/20Ss decimal (see example number 2). Please keep in mind that the DMS-40LCD points can be congured to suit the users particular readout require- meter from which the DMS-40LCD-4/20S is derived has an accuracy ments. To enable a desired decimal point place its DIPswitch to the specication of 3 counts (max.) thus, it may not always be possible ON position (up). Please note that the decimal points are merely to obtain the exact desired display readings. Achange of 1 count is placeholders, that is, they can all be on or all off they do not affect dened as the right-hand most digit going up or down by one. the meters operation and/or display readings. Display readings other than those shown in Table 1 are obtainable. For example, some negative readings with a 4mA input are possible. www.murata-ps.com/support MPM DMS-40LCD-420.C01 Page 2 of 5