DMR20-4/20 Series Loop-Powered, 4-20 mA LED Display Process Monitors with 2.5V Loop Drop FEATURES Muratas new DMR20-4/20 loop-powered digital process monitors feature a large, 2.5V maximum loop-drop (125 burden) for red LED model easy-to-read, bright LED display. All operating power is derived directly from the High-quality, 20-turn, span (gain) and zero (offset) Self-powered directly from 4-20 mA current loop, no external current loop itselfno external power source is required The large, 0.30 7.6 mm power source needed digits exhibit uniform intensity over the entire 4-20 mA operating range. Unlike other Fits round 1.20 inch 30.5 mm cutouts less than 1.00 inch loop-powered LED displays, the total maximum loop voltage drop for the red LED <25.4 mm behind-the-panel depth model is 2.5V Users no longer have to settle for difficult-to-read LCD displays in Ea sy-to-read, 0.30 inch 7.6 mm high LED digits with excellent loop-powered applications. dis play brightness available in red or green LEDs Both gain (span) and offset (zero) adjustments are performed with on-board, Supplied with EPDM rubber gasket and hex nut pr ecision, 20-turn potentiometers. All decimal-point and range-change selections are made on a six-position DIP switch featuring vibration-resistant, gold-plated High-quality, 20-turn, span (gain) and zero (offset) adjustments contacts. Unlike competitive meters, there are no jumpers or solder gaps to open Gold-plated DIP-switch for range and decimal points: Reliable sc rew-terminal input connections or close. Connections to the current loop are made via a reliable, two-position, screw-type terminal block. Rugged, polycarbonate, one-piece package The DMR20-4/20s DIP-switch and potentiometers accommodate hundreds of Protected against dust and water submersion to IP67/NEMA 6 different input-current/output-reading combinations. This versatility eliminates the need to order more costly, long-lead-time customs meters in applications in which several different-range meters are required. The round plastic housing fits standard 1.20 30.5mm panel cutouts. An EPDM rubber gasket and hex nut simplify installation and provide IP67/NEMA 6 protection to environmental dirt and moisture. SIMPLIFIED SCHEMATIC DIAGRAM For full details go to: DMR20-4/20 Series Subminiature 4-20 mA Loop-Powered 3 Digit LED Process Monitors Performance/Functional Specifications OPERATING AND SETUP INSTRUCTIONS Typical at TA = +25C, unless otherwise noted. DMR20-4/20S (Unipolar Reading Model) Current Loop Input Min. Typ. Max. Units As shipped, the DMR20-4/20S is factory calibrated to read 000 for a Full Scale Input Range +4 +20 mA 4 mA input and 1000 for a 20 mA input. The following worst-case procedure assumes the DMR20-4/20S is completely misadjusted, i.e., 175 Input Impedance both potentiometers and the DIP switches are randomly set .When Loop Voltage Drop - Red LED 2.2 2.5 Volts performing DIP-switch settings, be sure the DIP switchs small Loop Voltage Drop - Green LED 3.2 3.5 Volts actuators are firmly engaged in their fully-ON or fully-OFF positions. Overcurrent Protection 40 mA 1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully Performance counterclockwise, roughly 22 turns, and set SW1-SW6 to OFF. Sampling Rate 2.5 readings per second 2. Select DIP switch setting 2 in Table 1. Accuracy (1 minute warm-up) 0.05% FS 2 Count 3. Apply a precision 4 mA input to TB1 with proper polarity, and adjust Temperature Drift (0 to +60C) 0.15 0.3 Cnts/C R3 until the meters display reads 000. Display 4. Apply a precision 20 mA input and adjust R7 until the meters display Display Type and Size 3 digit, 0.30 / 7.6 mm high red LED reads 1000. Repeat steps 3 and 4 to make sure the adjustments Polarity Indication for negative reading do not affect one another. Overrange Indication 1 for negative Vin 5. If required, select the appropriate decimal point by setting SW1 and 1 for positive Vin SW2 per the settings shown in Table 3. Physical/Environmental NOTE: If a display reading other than 000 to 1000 is Operating Temperature 0 +60 C desired, refer to DIP Switch Settings Table 1 below for SW3 SW6 settings. Storage Temperature 40 +75 C Humidity (non-condensing) Table 1 0 85 % Case Material Polycarbonate DMR20-4/20S (Unipolar Model) DIP-Switch Settings Weight 0.65 ounces (18.5 grams) Display Readings The DMR20-4/20, using any of the DIP-switch settings described above, can 4 mA 20 mA SW3 SW4 SW5 SW6 withstand overcurrents, including those resulting from accidental reverse-polarity 1 000 to 1200-1999 Off Off Off Off connections, up to 40 mA without sustaining any damage. 2 000 to 750-1350 On Off Off Off Because DMR20-4/20 loop-powered meters employ active circuitry to convert the loop current into a voltage the meters effective series impedance varies in a 3 000 to 500-850 Off On Off Off manner that maintains the loop voltage drop relatively constant over the full 4-to- 4 000 to 350-600 Off Off On Off 20 mA current range. Listed input impedance specification applies at 20 mA with all DIP switches set to OFF. 5 000 to 250-350 On On On Off When looking up DIP-switch settings in the following Tables and the desired 6 000 to 150-250 On Off On On display readings can be achieved with either of two different settings, using the higher setting will produce less sensitive offset (R3) and span (R7) Examples (DMR20-4/20S-Unipolar Models) adjustments. Please keep in mind that the accuracy specification of 2 counts means it may not always be possible to obtain the exact desired display 1. Desired display readings are: reading. 4 mA = 0.00 Ordering Information 20 mA = 6.00 DMR20-4/20S-R-C Unipolar, loop-powered red LED meter Use DIP-switch setting 3 in Table 1 and enable decimal point DP2 by DMR20-4/20S-G-C Unipolar, loop-powered green ED meter setting SW1 to On and SW2 to Off. Apply 4 mA and adjust R3 so DMR20-4/20B-R-C Unipolar, loop-powered red LED meter the display reads 0.00. Apply 20 mA and adjust R7 so the display reads 6.00. Note: An M30 x 1.5 nylon metric hex nut and EPDM sealing 2. Desired display readings are: gasket are supplied with each meter. The -C suffix indicates 4 mA=000 RoHS compliance 20 mA =800 Panel Knockout Tools: Use DIP-switch setting 2 in Table 1. Apply 4 mA and adjust R3 so DMR20-1-KP 1.22 30.9 mm punch (no keying notch) the display reads 000. Apply 20 mA and adjust R7 so the display DMR20-2-KP 1.21 30.7 mm punch with 4 keying notches reads 800. For these display readings, no decimal points are used DMR20-3-KP Keyway Punch tool so set SW1 and SW2 both to On. www.murata-ps.com/support MPM DMR20-4/20.A01 Page 2 of 5