ac input power 3? digit a/d converter +v ?v ? + rms-to-dc converter cal. built-in current transformer led display power converter tb1 ab (l1) measured ac load current www.murata-ps.com www.murata-ps.com/support for full details go to www.murata-ps.com/rohs $ simplified schematic diagram figure 1. aca-20pc series simpli? ed schematic now available with wire lead cts aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 1 of 6 features built-in current transformers for direct measurement of 0 to 2/20/50/100 amps functionally complete: on-board current transformers scaling/interface circuitry precision a/d converters bright red led displays 8 different models subminiature, 1.38" x 0.88" package easy-to-read, 0.37"/9.4mm digits ac powered models 85-264vac @ 50/60hz "self-powered" 85-264vac, 2a and 20a models feature built-in load connections +5-40v dc powered models 2000v isolation; ul/csa recognized datel's new aca-20pc series are the ? rst digital ac ammeters to incorporate on-board current transformers (cts), and they are amazingly easy to use. simply pass the current-carrying load wire through the aca-20pcs on-board ct, apply power to the meter's two supply terminals, and youre instantly measuring ac currents over one of four ranges (0-2a with 1ma resolu- tion, 0-20a with 10ma resolution, or 0-50a and 0-100a with 100ma resolution). absolutely no external components, such as expensive low-value shunts or 5a "donut" cts, are required. meters are ac powered (120/220vac @ 50/60hz) or dc powered (+5-40v) and impose minimal loads (50ma max. and 120ma max., respectively) on their supplies. all models employ auto-zeroing circuits, precision bandgap references, and super stable thin-? lm resistors for unsurpassed accuracy (0.15%fs) and stability. the functionally complete aca-20pc ammeters provide all the scaling/interface circuitry to mate the cts output to a precision (3? digit) a/d converter. the a/d's output goes directly to drivers for the meters large (0.37"/9.4mm digit height), easy-to-read, led displays. ac-pow- ered units have on-board ac/dc converters, and wide-range dc-powered units have on-board linear regulators. ac-powered models can be powered by the same ac supply whose current they are monitoring. the 2a and 20a, 85-264vac, 50/60hz ("ac1") models feature additional on-board terminal blocks to supply power to the external load. all models provide 2000vdc iso- lation between the measured ac current and their power supply, and all are ul/csa recognized. each meter is housed in a subminiature, 1.38" x 0.88", epoxy-encapsulated package. total behind-the-panel installation depth is approximately 2 inches.
? the aca-20pc-1-ac1-rl and aca-20pc-2-ac1-rl have 4-position on-board terminal blocks. all other models have 2-position terminal blocks. ? speci? ed full-scale currents are those passing through the built-in ct's primary(load) circuit, over the frequency of 45-450hz. the overcurrent rating is a continuous rating that applies to the measured ac load current. it does not apply to any circuitry external to the meter. accuracy is guaranteed to the rated current. ? for the aca-20pc-2-ac1-rl, if the load is connected to the meter's on-board 4-position terminal block, the 20a full scale range requires 12awg solid copper wire on all connections. if 14awg solid copper wire is used, the current should be limited to 15a. see figure 3. ? all speci? ed maximum power supply currents are steady-state values. ac-powered models can draw higher surges at initial turn-on. ? maximum reverse polarity protection on "dc1" models is C40vdc. full-scale current (45-450hz) ? min. typ. max. units aca-20pc-1-xxx-xx C C 1.999 amps aca-20pc-2-xxx-xx ? C C 19.99 amps aca-20pc-3-xxx-xx C C 50.0 amps aca-20pc-4-xxx-xx C C 100.0 amps dms-30798-c C C 30.0 amps overcurrent rating ? 1.5 x rated full-scale current performance sampling rate 2.5 reading per second accuracy ? 0.15%fs 6 counts measurement type sine wave input, full-wave averaging, rms calibrated temperature drift (0 = +60c) C 0.2 0.4 cnts/c zero reading (vin = 0 volts) C001 000 001 counts dielectric withstanding voltage 2000 C C vdc power supply voltage ? aca-20pc-x-ac1-rl (47-99hz) 85 120 264 vac aca-20pc-x-dc1-rl +4.75 C +40 vdc power supply current ? aca-20pc-x-ac1-rl (47-99hz) C 30 50 ma aca-20pc-x-dc1-rl C +8 +12 madc power supply terminal block aca-20pc-1-ac1-rl and aca-20pc-2-ac1-rl (2a and 20a ac-powered models with 4-position terminal blocks): wire size and type 12-20awg (solid), 14-20awg (stranded) insulation strip length 0.25 inches screw tightening torque 4.4 lbin (0.5nm) 20% maximum rated current 20a with 12awg solid wire; 15a with 14awg solid or stranded wire maximum rated voltage 630v (vde 0110-v. group 2) 250v (vde 0110-v group 3) aca-20pc-x-xxx-xx (all other ac or dc-powered models with 2-position terminal blocks): wire size and type 16-24awg (solid or stranded) insulation strip length 0.25 inches screw tightening torque 2.2 lbin (0.25 nm) 20% display display type and size 3? digit, 0.37"/9.4mm high led overrange indication 1_ _ _ decimal point fixed, model dependent physical/environmental operating temperature 0 C +60 c storage temperature C40 C +75 c humidity (non-condensing) 0 C 95 % physical/environmental case material polycarbonate dimensions 1.38w x 0.88h. depth is model depen- dent (see mechanical speci? cation) weight: aca-20pc-1-xxx-xx 1.1 ounces (31 grams) aca-20pc-2-xxx-xx 1.1 ounces (31 grams) aca-20pc-3-xxx-xx 1.3 ounces (37 grams) aca-20pc-4-xxx-xx 1.5 ounces (43 grams) dms-30798-c 1.0 ounces (28 grams) performance/functional speci? cations typical at t a = +25c, unless otherwise noted. ? aca - 20pc - 1 - ac1 - rl - l - c 1 = 1.999a 2 = 19.99a 3 = 50.0a 4 = 100.0a rl = red standard bl = blue standard pgl = green standard ac1 = 85-264vac@50/60hz dc1 = +5-40vdc dms-30798-c: 30amp model with a wire lead ct and -ac1 power supply speci? cations. see mechanical section for dimensions. accessories: dms-20-cp panel cutout punch a dms-bzl4-c bezel assembly with sealing gasket is supplied with each ammeter. input range: led color: power supply: (45-450hz) ordering information leaded ct (100a model) rohs www.murata-ps.com/support aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 2 of 6
www.murata-ps.com/support aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 3 of 6 important! to ensure safe and reliable operation, aca-20pc ammeters must be installed and serviced by quali? ed technical personnel. contact datel if there is any doubt regarding ammeter installation and/or operation. 1. measurement type : aca-20pc ac ammeters employ a full-wave- recti? ed, average responding, rms-calibrated circuit to measure the stepped-down output of their on-board, l1 current transformer (ct) . stated accuracy speci? cations are measured using a sine-wave cur- rent at or close to the speci? ed full scale input level, at nominal line frequency. 2. calibration : periodic recalibration of aca-20pc ammeters is not required under normal, indoor operating environments. if user calibration is necessary, it should be performed by quali? ed technical personnel. calibration is performed with potentially lethal voltages applied to the aca-20pc and its associated wiring, with the speci? ed full-scale current ? owing through the ammeters built-in current transformer. a plastic, fully insulated adjusting tool must be used to access the recessed calibration potentiometer located on the back of the meter (see mechanical speci? cations). contact datel if additional informa- tion is required regarding calibration, setup, or any other technical issue pertaining to the aca-20pc. 3. wire gauges and fusing : wires speci? ed in the functional speci? - cations section must be used for making connections to aca-20pc series ammeters. all power-supply and load wiring must be rated for the supply voltages and currents they will conduct and must comply with any code or application-mandated requirements pertaining to the users speci? c installation. aca-20pc series ammeters are not internally fused. special attention must be paid to aca-20pc-1-ac1 (0-2a range) and aca-20pc-2-ac1 (0-20a range) ac-powered models when their built-in auxiliary termi- nal block connections on tb1 are used to supply power to an external load. the input supply wires connected to both the ammeter and the load must be fused according to the current rating of the wire gauge being used, in accordance with applicable regulatory codes, but not to exceed tb1s maximum 20a rating. if tb1 is not used to supply power to external loads, a 0.25a/250v time delay/time lag fuse must used. aca-20pc-3-ac1 (0-50a range, ac-powered) and aca-20pc- 4-ac1 (0-100a, ac-powered) models tb1 is to be used only for powering the ammeters internal circuitry; it must not be used to supply power to external loads. the supply wires feeding these models must be fused with a 0.25a time delay/time lag fuse, in accordance with applicable regulatory codes. wire insulation must be stripped to within 10% of the stated dimen- sions, and wires should be inserted into tb1 such that their insulation is not pinched by the screw terminal. 4. ac supply polarity and grounding : the two ac supply inputs, tb1-a and tb1-b, on ac-powered ammeters are not in themselves polarity sensitive, that is, they have no internal "ac lo" or "ac hi" technical notes designations. also, ac-powered aca-20pc ammeters do not include or require a connection to earth/chassis ground. however, in many applications, external ac loads which are connected directly to the aca-20pcs built-in auxiliary terminal blocks must be wired with proper polarity and connected to earth/chassis ground. 5. connector torque ratings : it is important to tighten tb1's screw terminals to their rated torque speci? cations of 4.4 pound-inches (0.5nm) for four-terminal ammeters (aca-20pc-1-ac1-rl and aca- 20pc-2-ac1-rl), and 3.6 pound-inches (0.4nm) for two-terminal ammeters. proper tightening will minimize connector losses and ensure safe, reliable operation. 6. 100 amp model (aca-20pc-4-xxx) : this models built-in current transformer requires a larger panel cutout width dimension. see mechanical speci? cations for more information. 7. dc-powered models : dc-powered models draw minimal supply currents and in most applications can be fused according to the supply wires maximum amperage rating. however, be sure to check and comply with all applicable codes and regulations to ensure proper installation and operation. 8. isolation : the on-board ct (l1) provides a minimum 2000vdc isolation between the current-carrying conductor passing through its primary circuit and the ammeter supply voltage connected to tb1. of course, this isolation rating only applies to applications in which the load wiring (i.e., the wire passing through the cts center hole) does not connect directly or indirectly to tb1-a or tb1-b. all connections to aca-20pc series ammeters must be made after the ammeter is securely attached to the panel and with all load and supply voltages de-energized (off). care should be exercised when passing the load-carrying conduc- tor through the meters built-in ct particularly when larger-gauge conductors are used. the position of the installed wire should be such that minimal forces are applied to the built-in ct, tb1, or to the ammeter itself. in high-vibration environments, adequate strain reliefs be used for all load and supply wiring. to ensure a secure panel-mount installation, datel recommends using the dms-bzl4 bezel assembly (with sealing gasket) supplied with each ammeter. also, please note that the aca-20pc-4-xxx 100a oversize ct requires a larger panel-cutout width of 1.350" (34.3mm). see mechanical speci? cations for detailed cutout and ammeter dimensions. following the four-step sequence shown in figure 2 below being careful not to apply excessive force or twisting motionsinsert the ammeter into the panel opening. when using the dms-bzl4 bezel assembly, install its sealing gasket so it is positioned between the ammeters front ? ange and panel front surface (see mechanical speci? cations). be sure to use and securely tighten all four screws supplied with the bezel assembly. panel installation
first pass and carefully dress one external load wire through the on-board ct (l1). then connect the ac supply and load wires to tb1 as shown. if required, verify that correct line-power polarities are applied to the external load (see technical note 4). ensure all wires are stripped and terminals torqued correctly. for proper operation, pass only one load wire through the on-board cts center hole. figure 3. 2a and 20a, 85-264v ac-powered models with auxilliary load connections figure 5. all dc-powered models figure 4. all other ac-powered models fused 85-264vac power 85-264vac to load fused 85-264vac power to load fused ac power supply to ac load ac supply C + fused dc power supply to ac load ac supply + C aca-20pc-x-acx aca-20pc-x-dcx aca-20pc-2-ac1-rl aca-20pc-1-ac1-rl step 2. step 3. step 4. step 1. figure 2. panel installation panel www.murata-ps.com/support aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 4 of 6 typical wiring diagram
aca-20pc-1 & 2-ac1-rl aca-20pc-3 series mechanical dimensions: inches (mm) tolerances: 2 pl dec 0.02 (0.51), 3 pl dec 0.010 (0.254) aca-20pc-4 series 2a and 20a, 85-264v ac-powered models aca-20pc-1 & 2 2a and 20a, all other models 50a models 100a models with pc-board mounted cts 1.00 (25.4) 2.01 (51.1) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.80 (20.3) 0.88 (22.4) 1.32 (33.5) 0.040 (1.02) 0.040 (1.02) cal. front view back view hole diameter: 0.27 (6.9) min. 1.00 (25.4) 2.01 (51.1) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.80 (20.3) 0.88 (22.4) 1.32 (33.5) 0.040 (1.02) 0.040 (1.02) cal. front view back view hole diameter: 0.27 (6.9) min. 1.00 (25.4) 2.12 (53.8) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.80 (20.3) 0.88 (22.4) 1.54 (39.1) 0.040 (1.02) 0.040 (1.02) cal. front view back view hole diameter: 0.35 (8.9) min. 1.00 (25.4) 2.53 (64.3) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.80 (20.3) 0.88 (22.4) 1.32 (33.5) 0.040 (1.02) 0.040 (1.02) cal. front view back view * * this model requires a panel cutout width of 1.350" (34.3mm) 1.33 (33.8) hole diameter: 0.55 (14.0) min. www.murata-ps.com/support aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 5 of 6 mechanical specifications
* 1.350 (34.3) for aca-20pc-4-xxx 100a model with pc-board mounted cts . ? ? bezel gasket #2-56 insert 0.156 (3.96) deep front view 1.280 (32.51) 0.187 (4.75) 1.826 (46.38) 0.838 (21.29) 1.626 (41.30) 1.07 (27.18) internal corner radii: 0.032 (0.81) max. 0.093 (2.362) dia (4 required) 0.116 (2.95) 1.336 (33.93)* 0.145 (3.68) panel cutout bezel installation and recommended drill and panel cutout 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 her ein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. speci? cations are subject to cha nge without notice. ? 2013 murata power solutions, inc. www.murata-ps.com/support murata power solutions, inc. 11 cabot boulevard, mans? eld, ma 02048-1151 u.s.a. iso 9001 and 14001 registered aca-20pc series digital, led-display ac ammeters with built-in current transformers mpm_aca_20pc.b11 page 6 of 6 aca-20pc-4-xxx-l (100a model) dms-30798-c (30a model) mechanical specifications, continued 1.00 (25.4) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.80 (20.3) 0.88 (22.4) 1.14 (29.0) 0.040 (1.02) 0.040 (1.02) ? ? cal. front view back view lead length: 2.0 (50.5) min. id: 100a model: 0.58 (14.7) dms-30798-c (30a): 0.35 (8.9) od: 100a model: 1.18 (30.0) dms-30798-c (30a): 0.87 (22.0)
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