Bulletin No. MDMV-F Drawing No. LP0266 Revised 08/09 Tel +1 (717) 767-6511 Fax +1 (717) 764-0839 www.redlion.net MODEL MDMV - MINIATURE DISPLAY MODULE D.C. VOLTMETER LCD, POSITIVE REFLECTIVE OR NEGATIVE TRANSMISSIVE WITH YELLOW/GREEN OR RED BACKLIGHTING 1 pA INPUT LEAKAGE CURRENT TYPICAL 200 mV FULL SCALE AUTOMATIC ZEROING CIRCUIT SELECTABLE DECIMAL POINTS POLARITY INDICATION 5 VDC POWERED FIVE SELECTABLE DISPLAY ANNUNCIATORS PANEL MOUNT OR PC BOARD MOUNT DESCRIPTION SPECIFICATIONS The MDMV is a small panel or printed circuit board mount digital voltmeter. 1. DISPLAY: 3-digit, 0.4 (10.2 mm) high digits. A minus(-) sign is displayed With advantages of accuracy, size, and ease of installation, it is an ideal when the voltage is negative. replacement for analog meters. The unit has a 3-digit LCD display with 0.4 2. DECIMAL POINTS: Selectable decimal points are activated at the rear (10.2 mm) high digits. The displays are available in positive image reflective terminal pins to allow the display to be read in tenths, hundredths or (black digits, reflective background) or negative image transmissive (illuminated thousandths. digits, dark background) with red or yellow/green backlighting. 3. ANNUNCIATORS: 5 selectable annunciators, BAT, V, A, and m are The integrated circuit is bonded directly to the printed circuit board and is activated at the appropriate rear terminal. mechanically protected. Internal electrical interface connections use elastomeric 4. POWER REQUIREMENTS: connectors to provide a corrosion resistant connection. This reliable construction Reflective Versions: 3 VDC to 6 VDC 500 A Max. also reduces the space requirements. Backlight Versions: 4.8 VDC to 6 VDC 25 mA Max. The MDMV module is designed to operate from a +5 VDC supply. The 5. INPUT RANGE: 0 to 199.9 mV DC. module measures input voltages from 0 to 199.9 mV DC relative to the supply 6. COMMON MODE: 1 V min. around common. common. 7. ACCURACY: (0.1% + 1 digit). Auto-zeroing is provided by the module, therefore no zero adjustment is 8. RESOLUTION: 100 v/Count. required. If the input signal exceeds the input range, the unit display will 9. OVERRANGE RATINGS, PROTECTION & INDICATION: indicate an overrange condition. Max Input Voltage: 6 VDC Max. The module has three selectable decimal point positions and five selectable Overrange Indication: Overrange is indicated by a 1 displayed in the annunciators (BAT,V,A,m,). The BAT (Battery) annunciator is used to indicate most significant digit and the blanking of the three least significant digits. a low battery condition, while the others are used to indicate Volts and Amperes. 10. READING RATE: 2 readings per second. 11. RESPONSE TIME: 1.5 seconds to settle for a step input change. 12. INPUT LEAKAGE CURRENT: 1 pA typical, 10 pA Max. Note: Recommended minimum clearance (behind the panel) for mounting clip installation is 2.25 (57.2)W x 1.5 (38.1)H. PANEL MOUNT UNIT PANEL CUT-OUT DIMENSIONS R .06 MAX., 4PL. +.03 In inches (mm) .93 (1.5) 1.06 -.02 (26.9) +.8 (23.6 ) -.5 +.03 1.68 1.81 (46.0) -.02 .06 .2 (5.08) MAX. SEE +.8 NOTE: BACKLIGHT MODELS: 0.50 (12.7) (42.7 ) (1.5) NOTE .14 (3.56) MIN. -.5 REFLECTIVE MODELS: 0.31 (8.0) PRINTED CIRCUIT BOARD MOUNT UNIT RECOMMENDED PCB LAYOUT UNIT OUTLINE .90 .19 (4.8) (22.9) .10 (2.5) 1.65 (41.9) SEE .2 (5.08) MAX. NOTE .12 (3.1) .14 (3.56) MIN. NOTE: BACKLIGHT MODELS: 0.56 (14.2) .042 (1.07) THRU, 15 PL. REFLECTIVE MODELS: 0.37 (9.4) 1SPECIFICATIONS (Contd) WIRING CONNECTIONS 13. COMMON MODE REJECTION RATIO: 70 dB. The electrical connections are made via 14. INPUT IMPEDANCE: 1000 M terminal pins located on the back of the 15. TEMPERATURE EFFECTS: unit. The terminal pins are on 0.100 Operating Range: 0 to 70 C center lines and can be mated with the Storage Temperature: -40 to 80 C RLC Model HWK7 cable assembly or Temperature Coefficient: 100 ppm/ C many standard 0.100 center line 16. CONSTRUCTION: High impact black plastic case. (Mounting clip connectors. When wiring the unit, refer to included with panel mount models.) Figure 3 to identify the wire position with 17. RELATIVE HUMIDITY: Less than 85% RH. the proper function. 18. WEIGHT: There are certain considerations that Reflective Panel Mount: 0.76 oz (11 g) should be observed when running the Reflective PCB Mount: 0.54 oz (7.8 g) signal wires. A length of wire can act like Backlit Panel Mount: 0.96 oz (13.6 g) an antenna, and the closer it is to a source Backlit PCB Mount: 0.75oz (10.4 g) of electrical noise, the more it becomes FIGURE 3 susceptible to that noise. These are a few rules that should be followed when running these wires. INSTALLATION 1. Never run signal wires in the same conduit or raceway with A.C. power lines, The MDMV meters are available in either a panel mount or printed circuit conductors feeding motors, solenoids, SCR controls, heaters, etc. board mount design. The panel mount units are provided with a mounting clip 2. Signal wires within enclosures should be routed as far away as possible from to securely hold the unit in the panel cutout. contactors, control relays, transformers, and other noisy components. Panel mount installation: 3. When shielded wire is used, connect the shield to the common of the MDMV 1. Cut panel opening to unit, and leave the other end of the shield disconnected and insulated from EXISTING PANEL THICKNESS specified dimensions. machine ground031 to .125 Remove burrs and clean (.79 to 3.18) 4. Connect common of the MDMV to machine ground at one point only. panel opening. 2. Install MDMV unit through LOCKING PIN FUNCTIONS TAB panel cutout as shown in +5 V - +5 VDC Positive Supply Terminal. Figure 1. COMMON - Negative Supply Terminal. COMMON - Negative Supply Terminal. 3. Slide mounting clip over rear INPUT LO - Signal Input Low Terminal. of unit until clip is against Normally connected to Common. back of panel. The unit has INPUT HI - Signal Input High Terminal. slots for the locking tabs to BACK PLANE - Back Plane Not Terminal. Any annunciator and/or BEZEL hold it in the panel opening. decimal point will appear when its terminal is connected to this terminal. Note: Hold the MDMV front MOUNTING CLIP BACK PLANE - Back Plane Terminal. Any annunciator and/or decimal bezel in place when sliding point NOT in use must be connected to this terminal. the mounting clip in to FIGURE 1 DP3 - Thousandths decimal point position. * position. DP2 - Hundredths decimal point position. * DP1 - Tenths decimal point position. * PCB mount installation: BAT - Low battery annunciator. * 1. Prepare printed circuit board hole pattern to the specifications. m - Milli annunciator. * - Micro annunciator. * 2. Unit should be hand soldered using good soldering techniques and hand V - Volt annunciator. * cleaned if necessary. A - Ampere annunciator. * MDMV SIGNAL INPUT * Note: All annunciators must be tied to either BACK PLANE orBACKPLANE The MDMV signal input range is from 0 to 199.9 mVDC with automatic zero adjustment. Signal inputs are not floating. The calibration does not require HANDLING PRECAUTIONS: This assembly contains electronic circuits adjustment, since the unit has been calibrated at the factory. that are damaged by static electricity. Before handling the assembly, If the input signal exceeds 200 mV, the module will go into an overrange discharge stray static electricity on your body by touching an earth ground condition. The unit will display a minus sign when the input high terminal is point. It is also important to handle the unit by the bezel assembly only. negative with respect to the input low terminal. Additionally, if it is necessary to handle a circuit board, be certain that hands are free from dirt, oil, etc., to avoid circuit contamination that may lead to BLOCK DIAGRAM malfunction. +5V BACKPLANE BACKPLANE BATTERY +5V A 1M PROCESS V INHI CIRCUITRY m INLO DP1 DP2 DP3 COMMON COMMON FIGURE 2 Note: Incorrect supply polarity may permanently damage the unit. 2 CALIBRATION POT A V m BAT DP1 DP2 DP3 BACK PLANE BACK PLANE INPUT HI INPUT LO COMMON COMMON +5V