Audio Precision DCX-127 User Manual Download Page 24

DMM Units

In DC Volts function, the reading may be displayed either in

absolute volts or as f(V), a function of volts, after modification by Offset

and Scale factors. Similarly, resistance readings may be displayed in

ohms or as f(O) with Offset and Scale. The “available units” list

includes only units valid for the presently-selected function (DC V or

ohms).

Auto/Fixed Range Checkbox

The voltmeter/ohmmeter may operate in autoranging mode or may

be fixed on any one of its full-scale ranges. When the DMM

Autoranging function is disabled (no check mark in Auto box), a Range

field is displayed and active for manual range selection. New entries

may be typed in or existing entries edited from the keyboard, and
completed by pressing the

E

key. When

E

is pressed, APWIN

software will select and display the most-sensitive range that can

handle the entered value.

Offset and Scale Values for f(V), f(O)

When f(V) (function of volts) or f(O) (function of ohms) units are

selected for the DMM, APWIN software computes the value to display

from the formula

display = (measu Offset) * Scale.

The “measurement” term is the value which would be displayed in

volts or ohms units. The “Offset” and “Scale” values are the contents

of the fields with those names, at the top right of the DCX-127 panel.

New entries may be typed into either field, or the existing entry edited,
from the keyboard followed by pressing the

E

key.

DCV/Ohms/Off Selection

The DMM (digital multimeter) can measure dc volts or ohms, or be

turned off, by use of the three buttons below the Auto Range check

box.

Operation

Panel

DCX-127 Multifunction Module User’s Guide

Page 19

Summary of Contents for DCX-127

Page 1: ...22 2019 will not be shipped to the European Union EU Customers may be able to purchase products from inventory that were placed on the EU market prior to July 22 2019 until supplies are depleted Audio...

Page 2: ...roduced or transmitted in any form or by any means electronic or mechanical including photocopying recording or by any information storage and retrieval system without permission in writing from the p...

Page 3: ...stallation 11 Mounting 11 Primary Power Considerations 11 Checking or Changing Power Line Voltage 11 Fuse Information 13 Changing Fusing Arrangement 14 Power Switch 15 Proper Environment 15 Connecting...

Page 4: ...so must be set to the same voltage as the nominal power source voltage 100 120 230 or 240V rms with the appropriate fuses installed The International Electrotechnical Commission IEC 1010 1 requires th...

Page 5: ...ecautionary instructions FUNCTIONAL EARTH TERMINAL This symbol marks a terminal that is electrically connected to a reference point of a measuring circuit or output and is intended to be earthed for a...

Page 6: ...sting VCA gain control linearity VCA distortion amplifier dc offset and power supply checks power amplifier load switching control loudspeaker voice coil resistance measurements temperature measuremen...

Page 7: ...DCX 127 Multifunction Module is a separate unit packaged in a one rack unit high case that may be rack mounted or used as a bench instrument The following sections describe the capabilities in greate...

Page 8: ...t may also be fixed on any range Reading rates of 6 readings per second or 25 readings per second may be selected Software features also permit displaying a computed value which is a function of resis...

Page 9: ...schematically on the front panel of the DCX 127 Voltage drop across these internal resistors produced by this current is internally measured at the and terminals The resistance of the two test leads...

Page 10: ...voltmeter leads so the resistance of the test leads is not included in the measurement The resolution of the reading varies with the range and with the reading rate as shown in Table 1 on page 3 DC V...

Page 11: ...controllable bias oscillators may be connected enabling MOL SOL sensitivity and other data to be taken automatically The dc outputs may be floated up to 2 volts away from ground See Figure 3 for the...

Page 12: ...or scaled decimal The format of the word bit to pin relationship may be selected as two s complement or 8 4 2 1 binary coded decimal BCD The strobe line pin 25 will be pulsed low each time a new valu...

Page 13: ...cks of a test disc The Trigger output pin 4 pulses high at the end of each delay portion of the settling process In a generator based sweep settling delay is the time after the generator steps to a ne...

Page 14: ...en the actual beginning of a sweep test and the leading edge of the gate output signal This delay time is entered at the bottom of the DCX software panel in the Gate Delay field An example application...

Page 15: ...ol of power lights and annunciators are among the possible applications The pin connections of these ports are shown below The current drive capability of each bit line is five milliamperes the output...

Page 16: ...recision order number RAK 212 allow either conventional flush front mounting or setback mounting to prevent the front connectors from protruding from the rack Primary Power Considerations Checking or...

Page 17: ...point up when the desired voltage is readable at the bottom with the indicator pin assembly seated in the notch on the board edge 5 Insert the voltage selector card into the housing with the printed s...

Page 18: ...using arrangement uses two 5 x 20 mm IEC approved type T fuses Both types should be rated 250 V Fuse current ratings are 200 mA for 100 120 V inputs or 100 mA for 230 240 V inputs Confirm this informa...

Page 19: ...y sliding up then away from the screw and lifting from pedestal at the other end refer to Figure 8 4 Invert the fuse holder and reassemble it on the Philips screw and pedestal and tighten the screw 5...

Page 20: ...o APIB connectors on its rear panel They permit connecting instruments in a daisy chain fashion between the computer s APIB card connector and the System One System Two or System Two Cascade APIB conn...

Page 21: ...240 VAC 100mA T SB 250V 100 120 VAC 200mA T SB 250V SUPPLY VOLTAGE FUSE FREQUENCY 50 60 Hz MAXIMUM POWER 20 VA SUPPLY VOLTAGE 100 120 230 240 VAC FUSE REPLACEMENT DATA 230 240 VAC 100mA T SB 250V 100...

Page 22: ...anels Toolbar brings up the small version panel shown in Figure 11 Holding down the S key while clicking on the toolbar icon brings up the large version shown in Figure 12 You can also click the Maxim...

Page 23: ...Volts Ohms Measurements Panel Operation Page 18 DCX 127 Multifunction Module User s Guide Figure 13 Connectors for volt ohms measurements Figure 12 DCX 127 panel large version...

Page 24: ...ompleted by pressing the E key When E is pressed APWIN software will select and display the most sensitive range that can handle the entered value Offset and Scale Values for f V f O When f V function...

Page 25: ...ccuracy and reduce noise under certain conditions When operating the DMM in the presence of high level radiated noise most commonly stray fields at line frequency When long test leads are used to meas...

Page 26: ...ually DC Output 1 and 2 Value Either DC output may be independently set to any voltage in the range 10 5 Vdc A new value may be entered or the existing value may be edited from the keyboard followed b...

Page 27: ...ector may be interpreted as 2 s complement or in 8 4 2 1 BCD binary coded decimal format Scale Factor Digital Input When g x units are selected at the Digital In display APWIN software computes the di...

Page 28: ...Bit 0 LSB LS digit 1 3 Bit 1 LS digit 2 4 Bit 2 LS digit 4 5 Bit 3 LS digit 8 6 Bit 4 5th digit 1 7 Bit 5 5th digit 2 8 Bit 6 5th digit 4 9 Bit 7 5th digit 8 10 Bit 8 4th digit 1 11 Bit 9 4th digit 2...

Page 29: ...l Out field will be presented to the front panel Digital Output connector in either 2 s complement or 8 4 2 1 BCD binary coded decimal format Scale Factor for Digital Output When h x units are selecte...

Page 30: ...edge of the gate signal That delay time is controlled by the Gate Delay field at the bottom of the DCX panel See Table 3 for Program Control Input and Output connector pin assignments Gate Delay Cont...

Page 31: ...pin numbering Pin Number Program Control Output Pin Number Program Control Input 1 Delayed Sweep Rate 1 Bit 7 MSB 2 Reset 2 Bit 6 3 Data Acquired 3 Bit 5 4 Trigger 4 Bit 4 5 Undefined 5 Bit 3 6 Sweep...

Page 32: ...eld and vice versa To change a value using octal decimal or hex units the desired unit must first be selected or the present unit accepted A new value may be entered into the field from the keyboard o...

Page 33: ...5 9 Figure 18 Connector J141 showing pin numbering Pin Number J141 Pin Number J141 1 Ground 9 Bit 0 LSB 2 Bit 7 MSB 10 5 V 3 Bit 6 11 5 V 4 Bit 5 12 15 V 5 Bit 4 13 15 V 6 Bit 3 14 Ground 7 Bit 2 15 G...

Page 34: ...05 100 mV 0 05 1 V Resolution 200 mV 200 V ranges 0 005 of range 0 025 of range 500 V range 100 mV 500 mV Input Resistance 10 MW 1 all ranges Common Mode Rejection 120 dB at dc and 50 Hz to 20 kHz Co...

Page 35: ...m Output Current 20 mA source 10 mA sink Residual Noise 10 V rms 10 Hz to 80 kHz bw Output Floating Characteristics Electronically balanced to allow low output terminal to float up to 2 Vpk Common mod...

Page 36: ...g UTILITY RESTORE command or following power cycling to the DCX 127 Pin 3 2 ms pulse when data is settled Pin 4 2 ms pulse at end of settling delay Pin 6 Sweep Gate low during sweeps Pin 7 A B Gate hi...

Page 37: ...CMOS compatible Outputs in series with 390 W resistors Input resistance typically 100 kW Maximum rated input 0 5V Output drive 5mA bit maximum Dimensions 17 in Wide 1 75 in High 10 5 in deep Operating...

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