Loop-Powered Isolators for Standard Signals For isolation of 0(4) 20 ma standard signals without power supply in 19" technology The Housing The integration of several modules on one Eurocard results in minimal cabling effort and a compact design, and is cost-effective. The full encapsulation design of the modules guarantees a high level of reliability even in extreme conditions. The Advantages The with a voltage drop of 1.2 V is the 1:1 isolator for all applications where loop-powered isolators are not suitable because of technical problems such as excessive voltage drop. The Task Galvanic isolation of measurement signals using 19" technology, cost reduction by means of minimum cabling in series production The Problems The application possibilities for looppowered isolators are mainly defined by the following critical data: Voltage drop Operating current Accuracy Load voltage Signal delay Isolation voltage Dimensions The Solution Knick's isolator has unmatched technical specifications. The isolator obtains its power supply as a voltage drop of the measurement signal without having a noticeable effect on it. This saves on power supply devices and cabling and increases the reliability accordingly. The Applications Galvanic isolation of input and output circuits of the supply voltage for 2-wire transmitters for the addition or other coupling of signals at different potentials to eliminate currents resulting from double grounding when insulation and test voltage are insufficient of high-potential signal sources for battery-powered devices with a central battery The Technology Knick's isolators with transformer-based isolation have specifications which far exceed those of all other looppowered isolators. They feature a chopper generator connected in series in the current path and current conversion which gradually changes from sine to square wave over the range. This avoids the accuracy-reducing current losses of normal parallel connected generators, considerably reduces the voltage drop, and ensures accurate transmission of even the lowest currents. 332
For up-to-date information, please visit www.knick.de Isolation Amplifiers Transmitters Indicators Process Analytics Portable Meters Laboratory Meters Sensors Fittings Facts Cost reduction through multichannel design Eurocard with up to 8 channels Minimum loading Voltage drop from 1.2 V, current transmission from 2 µa to 50 ma Good signal transmission Low signal delay No power supply required Cost savings due to lower wiring effort, no mains interference Maximum reliability No repair or failure costs Extremely high accuracy 5-year warranty Warranty 5 years! Warranty Defects occurring within 5 years from delivery date shall be remedied free of charge at our plant (carriage and insurance paid by sender). Product Line Devices Order No. Eurocards For up to 8 channels EK 15 41Mi 1) Power supply None, supply from input signal Options Order No. INTERMAS SP / K3-n04T front panel, plastic, gray, width 20 mm 301 1) Please indicate the required number of channels when ordering. Model EK 5... is still available for replacement purposes. 333
Loop-Powered Isolators for Standard Signals Specifications data 0 20 ma, 0 50 ma Operating current < 2 µa Equipment Voltage drop Overload capacity Max. 8 modules Approx. 1.2 V (20 ma) Approx. 1.6 V (50 ma) 100 ma, 20 V Output data Output 0 20 ma / max. 15 V (corresponds to 750 ohm load) 0 50 ma / max. 15 V (corresponds to 300 ohm load) Offset < 5 µa Residual ripple 2) < 1.5 mv pp / ma Transmission behavior Transformation error 3) Load error Rise or fall time 0.02 % full scale 0.02 % of the measured value per 100 ohms Approx. 2.5 ms at 500 ohm load resistance Isolation Test voltage Working voltage (basic insulation) 2.5 kv AC 4 channels 500 V DC at overvoltage category II and pollution degree 2 5 channels 500 V DC at overvoltage category II and pollution degree 1 according to EN 61010-1 For applications with high working voltages, ensure there is sufficient spacing or isolation from neighboring devices and protection against electric shocks. Standards and approvals Surge withstand 5 kv, 1.2/50 µs according to IEC 255-4 Immunity to interference 8 kv according to IEC 801-2 334
For up-to-date information, please visit www.knick.de Isolation Amplifiers Transmitters Indicators Process Analytics Portable Meters Laboratory Meters Sensors Fittings Specifications (continued) Further data Ambient temperature -25 +80 ºC Design Multipole connector Socket connector 4) Weight Eurocard 4 HP Type F according to DIN 41612, also refer to dimension drawings Type F according to DIN 41612 (wire-wrap connection), also refer to dimension drawings approx. 40 g per channel 2) Slightly increased residual ripple can occur with loads < 5 ohms 3) Temperature range 10 +70 C 4) Included in package content 335
Loop-Powered Isolators for Standard Signals Transfer function V in [V] voltage drop 15 10 Transmission = 1:1 I in = 20 ma I out = 20 ma V in V out + 1.2 V 5 0 0 5 10 15 V in [V] Output voltage Rise or fall time (10 90 %) of the output current 3.5 3 2.5 2 1.5 1 [ms] 0 1 ma 0 4 ma 0 20 ma 0.5 0 0 100 200 300 400 500 600 700 [Ohms] Load 336
For up-to-date information, please visit www.knick.de Isolation Amplifiers Transmitters Indicators Process Analytics Portable Meters Laboratory Meters Sensors Fittings Block Diagram + + Current input Z 20 V 1 µf Generator 100 khz 1:1 1 µf Z 20 V Current output Typical Applications Potential isolation for impressed current, current output Potential isolation for impressed output current, voltage output I in Iout I in A R Output Iout = I in Vout = R I in Potential isolation for addition of impressed currents I in 1 Output I in 2 e.g. grounded I in 3 Iout = I in 1 + I in 2 + I in 3 e.g. grounded 337
Loop-Powered Isolators for Standard Signals Typical Applications (continued) Potential isolation in two-wire systems Output Power supply Transducer 338
For up-to-date information, please visit www.knick.de Isolation Amplifiers Transmitters Indicators Process Analytics Portable Meters Laboratory Meters Sensors Fittings Dimension Drawing and Pin Assignments for Eurocard EK 15 19.98 8 3 6 1 128.4 2 7 4 5 100 Front panel, Opt. 301 173.5 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 d z + 1 6 3 8 Outp. 1 Outp. 6 Outp. 3 Outp. 8 5 4 7 2 Outp. 5 Outp. 4 Outp. 7 Outp. 2 Connector Front panel Option 301 Type F according to DIN 41612 INTERMAS SP/K3-n04 T, plastic, gray All dimensions in mm 339