DMS-EB-LP www.murata-ps.com 4-20mA Current Loop Application Board for DMS-30LCD Meters PRODUCT OVERVIEW FEATURES Loop-powered, no external supply required Includes gain (span) and offset (zero) adjustments Range and decimal point settings are DIP-switch selectable Covers hundreds of different ranges Reliable screw-terminal connections Low cost Description: The DMS-EB-LP was specifically designed for 4-to-20mA current-loop processmonitoring applications. The board simply mounts onto the rear of a DMS- 30LCD-1-5, allowing both the application board and the meter to be powered solely from the 4-to-20mA loop input. Align pin 1 of the board with pin 1 of the DMS-30LCD-1-5 and simply solder the two assemblies together. Features: Gain (span) and offset (zero) adjustments are both performed using precision, 22-turn potentiometers. Decimal point selections and range changes are all made on an eight-position DIP switch featuring gold-plated contacts — there are no cumberD1 some jumpers or solder gaps to contend with! ConnecON 12 R10 R3 SW1 tions to the loop are made via a reliable, screw-type Zero 1 6 7 8 2 3 4 5 C2 Adjust R12 terminal block. The only assembly tool required is a U1 SG10 R6 R9 TB1 screwdriver! R1 R8 + – TB2 C3 C1 R7 SG9 RJ4 Applications: The DMS-EB-LP's design accomGain Adjust D2 2 1 modates hundreds of different display reading combinations. This essentially eliminates the need to order "specials" in applications in which several differentrange meters are required. OEM customers should consider using Murata Power Solutions' DMS-30LCD-4/20S which already has the DMS-EB-LP soldered to a rugged DMS-30LCD-1-5 digital voltmeter. SIMPLIFIED SCHEMATIC 1 12 8 V+ 11 2 (+) INPUT HI 10 9 R4 2.21k + ANALOG COMMON C1 2.2μF 10V 1 4 BOOST U1 5 CAP– R5 698 GND 3 R10 10k C2 2.2μF 10V 4 3 8 REF. IN 5 R7 2k Gain Adjust 7 D2 RLZ5231 R2 2.94k +5V SUPPLY 2 V– CAP+ + (–) INPUT LO 6 D1 LM4041 5V RETURN DP3 DP2 DP1 + ON C3 2.2μF, 10V R12 5k SW1 RJ4 0 R6 90.9 TB1 1 2 + 1 R1 90.9 2 3 4 5 6 7 8 R8 26.7 R9 10.5 R3 5k Zero Adjust – LOOP RETURN LOOP INPUT 4-20mA Figure 1. DMS-EB-LP Schematic Diagram For full details go to www.murata-ps.com/rohs www.murata-ps.com/support MPM_DMS-EB-LP.C01 Page 1 of 3 DMS-EB-LP 4-20mA Current Loop Application Board for DMS-30LCD Meters Performance/Functional Specifications Display Reading (TA = +25°C) Input Full Scale Input 4mA to 20mA SW1 SW2 SW3 SW4 1. 000 to 100-300 On 2. 000 to 400-600 Off On On Off On Off Off 3. 000 to 700-1999 On Off Off Off 4. ±100 On On On Off Voltage Drop 7.5V, maximum 5. ±200 to ±300 On On Off Off Input Resistance 550Ω, nominal 6 ±400 to ±600 On Off Off Off Accuracy ±0.05%FS ±1 count 7 ±700 to ±1900 Off Off Off On Operating Temperature Range 0 to +60°C Temperature Drift ±100ppm/°C, typical Performance Physical/Environmental Storage Temperature –20 to +75°C Humidity 0 to 95%, non-condensing Dimensions 2.02" (51.31mm)L x 0.83" (21.08mm)W TB1 Wire Size and Strip Length: 18 to 26 AWG (solid or stranded) Strip Length 0.20" (5.08mm) Ordering Information Model DMS-EB-LP DMS-BZL1 DMS-BZL2 Current loop board Bezel assembly Bezel assembly with sealing gasket Operating and Setup Instructions As shipped, the DMS-EB-LP is factory calibrated to read "000" for a 4mA input and "1999" for a 20mA input but may require recalibration when connected to a DMS-30LCD-1-5 digital voltmeter. The following worst-case procedure assumes the DMS-EB-LP is completely mis-adjusted, i.e., both potentiometers and the DIP switches are randomly set. 1. Set R7 (full scale gain adjust) and R3 (zero/offset adjust) fully clockwise, roughly 22 turns, and place SW1-SW8 to OFF (down position). 2. Set SW1 to ON (up position). See DIP switch setting #3 in Table 1. 3. Apply a precision 4mA input, with proper polarity, and adjust R3 until the meter's display reads "000". 4. Apply a precision 20mA input and adjust R7 until the meter's display reads "1999". Repeat steps 3 and 4 to make sure the adjustments do not affect one another. 5. Select the appropriate decimal point by setting SW5, SW6 or SW7 to ON (DP1, DP2 or DP3 respectively). NOTE: If a display reading other than "000" to "1999" is desired, refer to Table 1 for SW1-SW4 settings. Table 1. DIP-Switch Settings NOTE: When looking up DIP-switch settings in the Table and the desired display readings happen to fall between two switch settings, try performing the adjustments with both settings to determine which one offers the better settability. Please keep in mind that the DMS-30LCD meter has an accuracy specification of ±2 counts (max.). Thus, it may not always be possible to obtain the exact desired display reading. Examples 1. Desired display readings are: 4mA ="0.00" 20mA = "2.00" Use DIP-switch setting #1 and enable decimal point DP2 via SW6. Apply 4mA and adjust R3 so the display reads "0.00". Apply 20mA and adjust R7 so the display reads "2.00". 2. Desired display readings are: 4mA =" –100" 12mA = "000" 20mA = "100" Use DIP-switch setting #4. Apply 12mA and adjust R3 so the display reads "000". Apply 20mA and adjust R7 so the display reads "100". Apply 4mA and the display should read "–100". For these display readings, no decimal points are used. Set SW5, SW6 and SW7 to OFF (down position). 3. Desired display readings are: 4mA = "-157.5" 12mA = "00.0" 20mA = "157.5" Use DIP-switch setting #7 and enable decimal point DP3 via SW7. Apply 12mA and adjust R3 so the display reads "000". Apply 20mA and adjust R7 so the display reads "157.5". Apply 4mA and the display should read "–157.5". 4. Desired display readings are: 4mA = ".000" 12mA = ".250" This example is not as straightforward as the previous three. Notice that 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 the chart, we can now select DIP-switch setting #2 and enable DP1 via SW5. Apply 4mA and adjust R3 so the display reads ".000". Apply 12mA and adjust R7 so the display reads ".250". www.murata-ps.com/support MPM_DMS-EB-LP.C01 Page 2 of 3 DMS-EB-LP 4-20mA Current Loop Application Board for DMS-30LCD Meters Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. ISO 9001 and 14001 REGISTERED This product is subject to the following operating requirements and the Life and Safety Critical Application Sales Policy: Refer to: http://www.murata-ps.com/requirements/ Murata Power Solutions, Inc. 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 do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. © 2015 Murata Power Solutions, Inc. www.murata-ps.com/support MPM_DMS-EB-LP.C01 Page 3 of 3