Loop Powered Process Indicator - Model A-705-20 Manual

A-705-20 LOOP CURRENT METERBulletin A-30-705Specifications - Installation and Operating InstructionUNIT DESCRIPTIONThe A-705-20 digital panel meter is a dual range, unipolar, 3 ½ digit, LCDcurrent meter. It is powered by the current loop being measured and hasselectable full scale ranges of 4-20mA and 10-50mA. This unit is designedwith a small case and easy calibration from the rear of the meter.MODEL NUMBER RANGEA-705-20 4-20mA TABLE OF CONTENTS Common Specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Installation Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Panel Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DPM Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Connections and Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electronic Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 -10 Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 LIST OF TABLES Decimal Point Location 1.XXX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Decimal Point Location 1X.XX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Decimal Point Location 1XX.X. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Decimal Point Location 1XXX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 LIST OF FIGURES DPM Dimensions & Panel Preparation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 DPM Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Meter rear Pinout Location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Headers & Jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electronic Assembly (Front) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Electronic Assembly (Back) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Electronic Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 SPECIFICATIONS • Power requirements–– None Required Power is derived from current • Range–– ±1999 • Accuracy–– ±0.1% Rdg., ± 1digit • Settling Time–– Under 1 sec. typical • Operating Temperature–– 0°C to +50°C • Storage–– -20°C to +70°C, 72 hrs., -10°C to +60°C, Indefinite. • Humidity–– 80% RH @ 40°C max., 70% RH @ 50°C max. • Decimal Points–– set by internal jumper, 1.XXX, 1X.XX, 1XX.X, 1XXX. • Polarity–– negative count; minus sign at left, positive count, plus sign at • Tempco–– 100ppm/°C typical • Weight–– approx. 2 oz. • Display–– 0.6½ high LCD • Recalibration Schedule–– 1 yr. within rated accuracy • Overrange Indication–– Positive overrange; Negative overrange; -1; • Size–– See outline dimensions. Installation Mechanical Installation The figure below shows a pictorial view and overall dimensions. Panel Preparation Prepare a panel cut-out as shown below at the desired location DPM Installation • Insert Meter in panel cutout from the front. • From rear, place side mounting clips in slots at Side Of Case. • Thread the screws into the clips and tighten against panel. NOTE: Shorting BC6 will change the function of J-5 to “loop - (50mA)”. This allows the option of switching the meter between 4-20mA and 10-50mA with a jumper rather than rewiring the installation see page 10 for reference. Electrical Connections The model A-705-20 accepts a 3 pin mating connector at the rear for decimal point and signal inputs. The figure below shows the pinout configuration and the location on the rear of the meter. OPERATION Signal Inputs: apply between pin 3 (Hi) and pin 1 (Lo 20mA) or pin 2 (Lo 50mA). - 20 mA - 50 mA + Signal CALIBRATION Allow 5 minutes warm-up with signal of 20mA. The number displayed on the A-705-20 readout is determined by the equation: D = S * I + O where “D” is the count being dis- played, “S” is a constant scale factor having the dimensions of counts per milliampere, “O” is a constant scale factor having the dimensions of counts, and “I” is the input current to the A-705-20. Example: Consider the case in which inputs of 4mA and 20mA yield displays of 000 and 100 respec- tively. Solving the equation for “S” and “O” gives DH - DL S = IH - IL O = DL - (S • IL) Where IH is the higher value of current input in milliamperes IL Scale = Display High - Display LowCurrent High - Current Low O (offset) in Counts BC4 BC5 +199.9 to 57.9 Shorted Open +61.6 to -60.8 Open Open -56.5 to -199.9 Open Shorted Since O in the example (-25.0) falls in the range +61.6 to -60.8, both BC4 and BC5 should be open. After BC1 , 2, 4, and 5 have been set, the potentiometers R9 and R12 (behind the front panel) need to be recalibrated for an accurate reading. The procedure is as follows: 1. Connect the positive input lead (current going into the meter) from a current stan- The following four sets of tables are for the different decimal point location as noted. DECIMAL POINT LOCATION 1.XXX (JUMPER J1 PIN 9 TO J1 PIN 10) “S” In Counts/mA BC1 BC2 0 to .057 Shorted Open .052 to .088 Open Open .083 to .140 Open Shorted DECIMAL POINT LOCATION 1.XXX (JUMPER J1 PIN 9 TO J1 PIN 10) O (offset) In Counts BC4 BC5 +1.999 to +.579 Shorted Open +.616 to -.608 Open Open -.565 to -1.999 Open Shorted DECIMAL POINT LOCATION 1X.XX (JUMPER J1 PIN 8 TO J1 PIN 7 OR 9) “S” In Counts/mA BC1 BC2 0 to .57 Shorted Open .52 to .88 Open Open .83 to 1.40 Open Shorted DECIMAL POINT LOCATION 1X.XX (JUMPER J1 PIN 8 TO J1 PIN 7 OR 9) O (offset) In Counts BC4 BC5 +19.99 to +5.79 Shorted Open +.616 to -.608 Open Open -5.65 to -19.99 Open Shorted DECIMAL POINT LOCATION 1XX.X (JUMPER J1 PIN 6 TO J1 PIN 7) “S” In Counts/mA BC1 BC2 0 to 5.7 Shorted Open 5.2 to 8.8 Open Open 8.3 to 14.0 Open Shorted DECIMAL POINT LOCATION 1XX.X (JUMPER J1 PIN 6 TO J1 PIN 7) O (offset) In Counts BC4 BC5 +199.9 to +57.9 Shorted Open +61.6 to -60.8 Open Open -56.5 to -199.9 Open Shorted DECIMAL POINT LOCATION 1XXX (NO JUMPERS) “S” In Counts/mA BC1 BC2 0 to 57 Shorted Open 52 to 88 Open Open 83 to 140 Open Shorted DECIMAL POINT LOCATION 1XXX (NO JUMPERS) O (offset) In Counts BC4 BC5 +1999 to +579 Shorted Open +616 to -608 Open Open -565 to -1999 Open Shorted Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10