DMS-20LCD-4/20 Series www.murata-ps.com 4-20mA Input Loop-Powered Ultra-Low 1.8V Loop Drop 3 Digit LCD Display Process Monitors FEATURES The DMS-20LCD-4/20 Series produces the lowest loop voltage-drop of any comparably priced, 4-20mA input, 3 digit LCD-display process monitors: 1.8V typical, 2.0V max. This Super-low loop drop: 1.8V typical, 2.0V max. super-low drop means its nominal loop resistance (burden) is less than 100 Ohms All op- Self-powered, no separate supply required erating power is derived solely from the 4-20mA loop currentno separate power source Unipolar, Bipolar, and Positive Reading Models is required The simple 2-wire hookup allows the DMS-20LCD-4/20 Series to be connected anywhere in the loop Subminiature packageLess than 0.90 behind-the- All decimal-point and range-change selections are made via a six-position DIP panel depth switch featuring vibration-resistant, gold-plated contactsthere are no jumpers or solder Large, 0.37 /9.4mm high, sunlight-viewable gaps to ever open or close. Both gain (span) and offset (zero) adjustments are performed LCD display with precision, 20-turn potentiometers. Three different models are available for unipolar, Non-interacting gain (span) and offset (zero) 20-turn bipolar, and positive display reading applications. The DMS-20LCD-4/20s DIP switch and potentiometers adjustment potentiometers can accommodate literally hundreds of different input-current/ output-reading combinations. And, connections to the current loop are made via a reliable, DIP-switch selectable range and decimal points two-position, screw-type terminal block. Hundreds of different input/readout combinations The DMS-20LCD-4/20 Series subminiature package houses a large, 0.37 /9.4mm Vibration-resistant package reliable screw-terminal high digits, LCD display that can be read in virtually all lighting conditionsincluding direct input connections sunlight. An optional bezel assembly, featuring screw fasteners and a rubber seal, simpli es panel mounting and provides excellent resistance to environmental dust and moisture. All these outstanding features combine to make the DMS-20LCD-4/20 Series the perfect meters for OEM 4-20mA current-loop process monitoring instrumentation. SIMPLIFIED SCHEMATIC DIAGRAM 3 DIGIT A/D DATA CONVERTER 132 R3 R7 DP1 DP2 DP3 ZERO GAIN ADJUST ADJUST BAND-GAP REFERENCE CIRCUIT ON ON DIP SWITCHES 11 2 3 4 5 6 1 2 3 4 55 66 +5V 5V TB1 12 CURRENT TO DC/DC VOLTAGE CONVERTER CONVERTER For full details go to + www.murata-ps.com/rohs LOOP INPUT www.murata-ps.com/support MPM DMS20LCD-420.C01 Page 1 of 6DMS-20LCD-4/20 Series 4-20mA Input Loop-Powered Ultra-Low 1.8V Loop Drop 3 Digit LCD Display Process Monitors Performance/Functional Speci cations Typical at TA = +25C, unless otherwise noted. performing DIP-switch settings, be sure the DIP switch s small actuators Current Loop Inputs Min. Typ. Max. Units are rmly engaged in their fully-ON or fully-OFF positions. Full Scale Input Range +3.8 +20.4 mA 1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully 80 100 Input Impedence clockwise, roughly 22 turns, and place SW1-SW6 to OFF. 1.8 2.0 Volts Voltage Drop 2. Select DIP switch setting 2. Overvoltage Protection 40 mA 1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully Performance clockwise, roughly 22 turns, and place SW1-SW6 to OFF. Sampling Rate 2.5 reading per second 2. Select DIP switch setting 2. Accuracy (1 minute warm-up): 0.05%FS 1 Count 3. Apply a precision 4mA input, with proper polarity, and adjust R3 until the meter s display reads000 . Temperature Drift (0 = +60C) 0.15 0.3 Cnts/C 4. Apply a precision 20mA input and adjust R7 until the meter s display Display reads1000 . Repeat steps 3 and 4 to make sure the adjustments do Display Type and Size 3 digit, 0.37 /9.4mm high LCD not affect one another. Polarity Indication for negative readings 5. Select the appropriate decimal point by setting SW4, SW5 or SW6 to Overrange Indication1 for negative inputs ON (DP1, DP2 or DP3 respectively). 1 for positive inputs NOTE: If a display reading other than000 to1000 is desired, Physical/Environmental refer to DIPSwitch Settings Table 1 for SW1SW3 settings. Operating Temperature 0 +60 C Storage Temperature 20 +75 C Examples (DMS-20LCD-4/20S-Unipolar Model) Humidity (non-condensing) 0 95 % 1. Desired display readings are: Case Material Polycarbonate ON Weight 0.6 ounces (17 grams) 4mA 0.00 20mA =6.00 1 2 3 4 56 The DMS-20LCD-4/20, using any of the DIP-switch settings described above, can withstand overcurrents, including those resulting from accidental reverse- Use DIP-switch setting 3 in Table 1 and enable decimal point DP2 via polarity connections, up to 40mA without sustaining any damage. SW5. Apply 4mA and adjust R3 so the display reads0.00 . Apply Because Murata Power Solutions DMS-4/20 loop-powered meters employ active 20mA and adjust R7 so the display reads6.00 . circuitry to convert the loop current into a voltage, the meters effective series 2. Desired display readings are: impedance varies in a manner that maintains the loop voltage drop constant ON over the full 4-to-20mA current range. Listed impedance speci cation applies at 4mA =000 20mA. 20mA =800 123 4 5 6 Use DIP-switch setting 2 in Table 1. Apply 4mA and adjust R3 so the Ordering Information display reads000 . Apply 20mA and adjust R7 so the display reads DMS-20LCD-4/20S-C Unipolar reading, loop-powered LCD meter800 . For these display readings, no decimal points are used. Set DMS-20LCD-4/20B-C Bipolar reading, loop-powered LCD meter SW4, SW5 and SW6 to OFF. DMS-20LCD-4/20P-C Positive reading, loop-powered LCD meter DMS-BZL3-C Bezel assembly 3. Desired display readings are: ON DMS-BZL4-C Bezel assembly with sealing gasket 4mA =.000 DMS-20-CP Panel cutout punch 12mA =.250 12 3 4 56 A panel-mount retaining clip is supplied with each model. This example is not as straightforward as the previous two. Notice that See www.murata-ps.com/dpm-availability for model-speci c availability. 12mA is exactly halfway between 4mA and 20mA. If we assume that the input could go up to 20mA, the display reading would then be: 2 x .250 or.500 . From Table 1 we can now select DIP-switch setting 4 and enable DP1 via SW4. Apply 4mA and adjust R3 so the display OPERATING AND SETUP INSTRUCTIONS reads.000 . Apply 12mA and adjust R7 so the display DMS-20LCD-4/20S (Unipolar Reading Model) reads.250 . As shipped, the DMS-20LCD-4/20S is factory calibrated to read000 for a 4mA input and1000 for a 20mA input. The following worst-case procedure assumes the DMS-20LCD-4/20S is completely mis-adjusted, i.e., both potentiometers and the DIP switches are randomly set. When www.murata-ps.com/support MPM DMS20LCD-420.C01 Page 2 of 6