Topward TMV-360 User manual

INSTRUCTION MANUAL
AC MILLIVOLT METER
MODEL:TMV- 360/380/381 /381 R

TABLE of CONTENTS
General •••
Features ••
Specifications.
Circuit Description •••
Block Diagram ••••• • •••
Functional Controls.
Operation ••••
Applications.
Maintenance ••
Alignment.... • •••••
Cautions For Use ••
Component Layout • •
Circuit Diagram •••
.•.. 2
4
7
• 11
.1 2
••••• 1 5
• •••••. 1 9
• 2 4
• 2 5
• •• 2 8
• ••• • • • • 2 9
• 3 0

TIYIV-360
TMV-380
TMV-381

GENERAT
TOPWARD'S Model TMV-380, TMV-381 and TMV-381R are dual-channel electronic
voltmeter sets having two independent AC voltmeters in a single cabinet. Two-
pointer meter allows easy dual measurem ents and inter-channel comparisons.
They also are wideband, super high sensiti ve voltmete r for use anywhere
voltage measurements are made. The easy-to- use vo lt met er provides frequency
response as wide as 5Hz to 1 MHz, measura ble ra ng e from 0.3mV to 100V, (1 mV
to 300V for TMV-380) and input impedance of 10 M The optional remote
control feature is convenient for measure ment in pr oducti on lin es.
The Model TMV-381R range indicator lamp is prepared on t he top side of
pointer meter and remote control of range sw itc hing is ava ila be to check
input range.
dual
the
TMV-381R is attached line decorder and the m eas u ri ng range can be remotely
controlled by ACS-017.
This manual was prepared in common to fo ur v ersions, major differences of
which are as follows,
TMV-381, TMV-381R 300uV maximum sensitivity.
TMV-380, TMV-360 1mV maximum sensitivity. (T MV -360 single channel only)
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FEATURES
A. All solid state circuitries provide high stability, rather short warm-up
time, and low power consumption.
B. Two power source circuits, positive and negative, are provided for very
stable DC bias and recover from any overload in a very short time.
C. Small-sized compact construction is easy to carry and large-sized two-
pointer meter is easy to read .
0. Two-color, four-scale dial plate and red and black pointers allow quick,
and accurate voltage reading.
E. Number of adjusting trimmers are minimized
precisely calculated in open loop gains and are
metalfilm resistors as accurate as 1%
with amplifiers that are
negative feedbacked th rough
A mplifier characteristics therefore are free from secu lar cha nge.
F. Input impedance is as h igh as 10 MD on all ranges and it s parallel
capacitance less than 45 pF.
G. Indirect attenuator switching by relay and FET ( field-ef fect transistor )
sw itch provides higher reliability,signal-to-noise ratio, and inter-channel
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crosstalk than most previous direct method of rotary switch.
H. Remote range selection is possible in a simple way that optional remote
control unit "ACS-017" can be connected to TMV-381R, since is attached remote
function.
I. Two channel ranga setting can be made either individually or together (in
interlocked manner).
J. A ground mode selector may float measuring circuit above ground.
- 3 -

SPECIFICATIONS
Values brackets (
l'letar Section
Measurable voltages:
Error:
dB:
dBm:
Frequency response:
Input impedance:
Durable input voltage :
Stability:
are for the TMV-380, TMV-360 version
0.3mV-100V in 12 ranges: 0.3mV, 1mV, 3mV, 10mV, 30mV,
100mV,
0.3V, 1V, 3V, 10V, 30V and 100V full scales.
(1mV-300V in 12 ranges: 1mV, 3mV, 10mV, 30mV, 100mV,
300mV, 1
V, 3V, 1 OV, 30V, 1 OOV and 300V full scales.)
-90- +40dB ( DdB= 1 V).
-90 ,._ +42dBm ( -90 -+46dBm) ( Od8m=1 mW, 600.0.).
Within+- 3% of full scale at 1kHz.
+- 10% at 5Hz- 1MHz,
+- 5% at 1 DHz- 500kHz and
+- 3% at 20Hz- 200kHz as
+- 2% at 30Hz--... 1OOkHz
referenceed to 1kHz response.
10Mn +-5%, with less than 45pF parallel capacitance.
500V (DC + AC peak )
100V peak (DC+AC peak)
up to -1DdB. ·
Within +-0.5% of full scale for +-10% line voltage
fluctuation.
- 4 -

Temperature
coefficient:
Residual voltage
Operating
temperature:
Relative humidity:
Crosstalk, Individual:
Interlock:
+-0.08~/°C.
less than 30uV at shorted inputon TMV-381,
100uV on TMV-360
and 380.
o ~50°C'.
80~.
Less than -BOdS with other input terminated with 600D.
Less than -SOdB with other input terminated with 600.0.
Residual noise: Less than 30uV with input shorted on 0.3mV range.
Amplifier Section
Gain:
Output voltage:
Output impedance:
Distortion:
Signal-to-noise ratio:
Frequency response:
Power Supply Section
Line voltage:
Power consumption:
Accessory
Approx. ?OdB.
1Vrms
+-10~.
soon +-1 o~ .
Less than 1% at full scale. (Rated by signal-to-noise
ratio in 0.3mV. 1mV and 1V ( 1mV 3mV and 3 V )
ranges.)
Over 40dB at full scale. (Over 30dB at 0.3mV ( 1mV )
range)
Wethin +-3d8 at 5Hz- 500kHz.
115V,230V AC +-10%, 50/60Hz .
Approx. 1 OW
TMV-360 ACS-001x1, TMV-380 ACS-001x2, JMV-381 ACS-003x2.
- 5 -

Dlimensions~
12S(138)W X 190{21~)H
X 238(268)Dmm.
Values
in ( )
include
protrusions.
Net weight:
Jkg.
Accessories
Power cable: 1 pc.
Input
cable:
BNC cord,
2 pes.
Instruction manual: 1 copy.
- 6 -

CIRCUIT DESCRIPTION
In studying
Figure 1. the
the operation of each circuit in voltmeter please refer
"Block Diagram "• and the Schematic Diagram on the back.
Outline of Operation
to
A signal voltage to be measured. which is input from the INPUT connector. is
passed through the First Attenuator and is converted to a low impedance by the
lmpedance Converter. The impedance-conv~rted signal is normalized. or further
attenuated in proportion to 1 Vrms fullscale value through the Second and
Third Attenuator. The normalized signal is magnified 20-fold by the Main
Amplifier and is fed to the Output Amplifier and the Absolute-Mea n Value
Detctor.
The Output Amplifier magnifies the signal 50-fold and feeds to the OUTPUT
connector. The Absolute-Mean Value Detector converts the signal from the Main
Amplifier to DC current in proportion to the absolutemean value. The
converted signal activates the Meter.
The Attenuator Control encodes the signal led fro m the R ANGE selector to
generate an Attenuator Control s ignal. This signal controls the First.
Second. and Third Attenuators to set the sensitivity corresponding to each
range.
The Power Supply feeds to the functional circuits +-5 V DC voltages
stabilized by its IC regulator.
- 7 -

ascription of Functional Circuits
1. First Attenuator
A resistance divider attenuator. The amount of attenuation is switched in
two s teps by relay contacts: OdB and -60dB.
2. Impedance Converter
A three-fold no-phase-inverison amplifier having a FET differential input.
This converts the First Attenuator output signal to a suffi c iently low
impe d ance and feeds to the Sec ond Attenuator.
3. Second Attenuator
A resistance divider attenuator. The amount of attenuation is switched in
two steps by rela y contacts : O dB and -30 dB .
4. Third Attenuator
A resistance divider attenuator.
four steps by a FET switch: 0 dB, -10
The amount of attenuation is s witched in
dB, -20 dB, and -30 dB.
5. ~aln Amplifier
A wideband, non-phase-inversion amplifier hav i ng a
This has high input impedance, low output impedance, and
output signal level is 20 mVrm s for the fullscale read on
- 8 -
differential
20-fold gain.
the Meter.
input.
This

6. Output Amplifier
A wi deband, non-phase-inversion amplifier with a diff erential input . Thi s
wo r ks stabl y even for capac itive loads. The gain i s 50 - fold and the out put
impe dance 600D The output signal level is 1 Vrms for the fullscale read · on
the Meter.
7. Absolute-~ean Value Detector
An absolute-mean value detector comprised of a high t h rough-rate, high
gain amplifier with a differential input. This has a ~ er y good l i nearity as
negative feed back by the voltage detected from the current flow in g through
the Mete r load. In switching, thi s provides a sufficiently wi de freq u ency band
so that the high frequenc y pa hse compensatio n circuit is reset.
B. Attenuator Control
A logic control circuit comprised of a diode matri x and outpu t buffer
transistors. This encode s a 12-bit sign al from the RAN GE selector switc h to 6-
bit signals, which c ontrol the Fi r s t, Second, and T hird Attenuat ors. The
rem ote control ca nne ctor is con necte d to th i s circuit .
9. Power Supply
A power source of converting the AC input to +-SV DC outp u ts to suppl y.
Thi s has a s ilicon diode bridge for full-wave r ectificatio n, high - c apacita nce
electrolytic capacitors for smoothing, and an I C re gulator stab ilizatio n .
- 9 -

1 0. RANGE-CH1 & 2 Selector
A 12 -c o ntact rotary switch f or setting a desired channel 1 and 2 measurable
voltage range. This fee ds a signal corre s ponding to the range into the
Attenuato r Control .
11. RANGE-CH 2 Selector (Below descri ption are in TMV -380, TMV-381 only)
A 12-contact rotary s witch for sett ing a desired channel 2 measurable
voltage range. T hi s feeds a sig nal c orre sponding to th e rangQ into the
Attenuator Control.
12. CH2 SELECTOR Switch
A selector which is used to select either individual or interlocked range
setting of channels 1 and 2. This selector, when set on the individual side
(right position), allow s the RANGE-CH2 selector 11 to set a channel 2 range
independently. At the left p ositio n (interlock s ide) , the RANGE-CH1 & 2
selector 10 ca~ set both channel 1 and 2 ranges at a time.
13. GNO ~ODE Switch
A switch which is used to disconnect the input negative circuits from the
casing ground. The switch, when in the GND position, connects both channel 1
and 2 negative leads to the grounding pas~ (casing). At the OPEN
position, the input negative connectors are floated off ground. This allows
grounding on the signal source side.
- 10 -

BLOCK DIAGRAM
O~EN
CN I" + (.1
H ~- - --- ._____. _-r- --+,
= G "'' O
Figure 1
Block Diagram
11

FUNCTIONAL CONTROLS
........-, T OPW ARO ELECTR IC INSTIWMlfrlTS CO. LTO .
.. .. 2 CHAN NEL AC VOLT METER MOO E'-'T MV· 311
- 0~
0
0
l:. .1
..
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i.·
..
.
.. ~
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"!: .:. . ..
\-1'-- - ../ • .J '!' •v• cno • "~
t••c:; c:: = ~ . ~:;
-=.' .'
-::-.·
L----- ------ i=== == ======~~
Figure 2 - Front Panel View
0 0
Figure J - Rear Panel View
- 12 -

Front panel (see Figure 2)
1. Power on indicator (LED).
2. POWER - Power on-off switch.
3. RANGE-CH1 & 2 - Channel 1 and 2 attenuator selector.
4. INPUT 1 - Channel 1 input connector.
5. CH2 SELECTOR - Individual-interlock range setting selector.
6. INPUT 2 - Channel 2 input connector.
7. RANGE-CH2 - Channel 2 attenuator selector.
8. GND ~ODE - Negative input f~oating switch.
9. Dual-pointer meter.
Rear panel (see Figure 3)
10. GND - Casing grounding pos t.
11. OUTPUT-2- Channel 2 monitor output co nnector .
- 13 -

12. Line voltage selector.
13. Power cable connector.
14. Fuse holder.
15. OUTPUT-1 - Channel 1 monitor output connector.
16. CONT-INPUT -TMV-380, TMV-381 types Remote control mouriting hole.
TMV-380R types connector for Remote control.
23. Range indicator lamp (TMV-381R only).
-14 -

OPERATION
Set-up
Values in brackets (
1. Press the POWER
emitting diode, will
j are for the TMV-380, TMV-360 version .
pushswitch 2 in. The Power-on indicator 1,
light, indicating that power has been applied.
a
light-
2. Plug the signal calbes into the INPUT 1 and 2
connectors 4 and 6.
3. Set the CH2 SELECTOR switch 5 to the i n di v idual side (right position).
4. Set the RANGE-CH 1 & 2 selector 3 and the RANGE-CH2 selector 7 to "100V
[300V]". To measure an AC voltage superimposed on a DC voltage, be sure to set
the selectors to the positions before connectin g the cables to points to be
measured. Otherwise, the DC voltage causes a high surge, which could burn
voltmeter.
5. Set the GNO ~ODE selector 8 to "GND" (right position).
6. Connect the cables to points to be measure.
7. Turn the selectors 3 and 7 for proper ranges until each Meter pointer
switngs over one third of the fullscale.
B. Read the Meter.
- 1 5 -

(1). Voltage Scales
There are two black voltage scales: a scale A graduated 0 to 10 and a scale
B 0 to 3. When the RANGE se l ector 3 is at "1 V", for ex ample , the division 10
on the scale A indicates 1 V. At the "300mV" posi ti on, the division 3 on the
scale B indicates 300mV. Si milarly, the other RANGE selecto r positions show
their full scale values.
(2) . dB Scale
In general, the dB values are ex pressed in dB V wh ich is a unit referenced
by 0 dB equal to 1 V. (Note that the TMV-380, TM V-360 version has no dB
scale. ) The division 10 at the scale A corre spo nd s t o 0 dB on the red dB
scale, which is a voltage ratio sc ale. Sinc e the RANGE se lector has 12 range
positions in steps of 10 dB, the voltage ratio of 0.3mV to 100 V is 110 dB
attenuation. Assume a reference voltage level on th e scale A be 1 V with the
RANGE selector at "1 V", a given voltage c an be rea d as low as -70 dB (0.3mV)
by t u rning the selector downward. Fu rther, as t he sc ale A allows reading to -
20 dB (0.03mV ) , you can conti n uously measure the v oltage ratio as high as -90
dB (0.03m V to 1 V) . The read of -90 dB means a si gna l-to-nois e ratio of around
10 dB. Al so , the dB s cale allows continuou s m ea su ri ng up to +40 dB (1 to 100
V) by turing the selector upward.
(3). dBm Scale
In general, voltmeters have a re f eren ce le v el division of 0 dBm equal to
- 16 -

0.775 V (1mW power) induced across a 600n resistance load , Therefore, the
red dBm scale is available to measure a power level referenced to 0 dBm, with
the impedance of the g1ven power circuit b eing 600fi pure resistance. Where
measured across specific resistance loads, for example, 10kil other than
the 600fi load, the levels are sometimes expressed in dBs.
How to Use Remote Control
Availability of the optional Remote Control is one of outstanding features
of Voltmeters.
T~V-3B1R : To attach the Remot~ Control, remove the blind plate
at the rear of voltmeter. Install and plug the optional conn ec t or into the 16-
pin connector on the PC board. Wire it to the multi - pin connector (plug)
supplied with the option. Also, wire its pins to a RANGE pushs w itch or rotary
switch and to a PANEL-REMOTE switch and individual-i nt er lock s w itch (toggle
switch, pushswitch or slide switch). These switches allows you to change the
measuring voltage range on your voltmeter from a distance place.
T~V-3B1R type: The measuring range of TMV-381R can be remetely coutrolled by
ACS-017(option ) . The outputs of remote cantrall c onn ector 16 are as table 1
and the input and output or each range are as tabel 2.
- 17 -