ad2s34 Analog Devices, Inc., ad2s34 Datasheet - Page 5

• Manufacturer Part Number: ad2s34
• Description: 14-bit,dualchanne Resolver -to-digitalconverte
• Manufacturer: Analog Devices, Inc.

ANALOGOEVICES fAX-ON-DEMAND HOTLINE
REV. A
where
(I>.VI is multiplied
give:
These signals are subtracted
or
cillator (VCO) form a closed-loop system which seeks to null sin
(0--<1». W hen this is accomplished, the word state of the up-
down counter, q" equals, to within the rated accuracy of the
converter, the resolver shaft angle, fl.
commands and wait states. As the transducer moves through a
position equivalent to the least significant bit weighting, the out-
put digital word is updated by one LSB.
digital position output pins.
Both channels operate continuously and independently of each
other. The shared digital output from either channel is available
as selected by switching the channel select inputs.
To illustrate the conversion process, the resolver format inpUt
signalsare represented
Assume that the current word state of the up-down counter is
A phase sensitive detector, integrator and voltage controlled os-
PRINCIPLES OF OPERA nON
The AD2S34 series operate on a Type 2 tracking closed-loop
principle. The oUtpUt digiTal word continually tracks the posi-
tion of the resolver shaft without the need for external convert
Each channel is identical in operation, sharing power supply and
(1
is the angle of the resolvershaft.
K Eo sin wI Isin e cos q,--cos {}sin q,!
R,
R,
s.~
s,
R.
R,
ns,
~~/
by cos
R'SOLVER
RESOlVER
V2 = K Eo sin wI cosB
TWISTED PAIR
VI = K Eo sin wt sin 8
K Eo sin wt sin H cas q,
K Eo sin lOt cos H sin q,
~J55
KEosinwlsinIO""q,!
'N"'VIDUAl
SCREENED
1
by:
CA.BlE
A
R
:
$.,
S,
s
$,
q,
PHASE lEAD
by the error amplifier to give:
~L_::.xs
and V2 is multiplied
/
~
~.r~--:-
-~~-~r---
'"
~~==f---
~~-:. ~
""
~ r---r---
0
1----
l:::5C5
-----..
ARC TA.N
OPTIONAL
----.
----
R
-
Page
,;;mc
C
PHASE S HIFT c~
Figure 1. Connecting the 2534 to Resolvers
.
.--------------
~
,
"'--;;--i;;-;
1
8
PHA."
by sin
'OPTIONAL
~
OPTIONAL
PHASE
OR LAG
CIRCUIT
PHAS£ lEAD
OR lAG
CIRCUIT
LAG
0
LEAD
q,
ARC TA." 2n IRC
to
C
---
~
-5-
The digital oUtpUt is taken from Pins J-14. Pin I is the MSB,
The interrull oscillator output (REF OUT) should be connected
circuit to the reference inpUts (REF A & REF B). See Figure I
The signals applied to REF A and REF B should be ac coupled
as shown in Figure I. This ac coupling can be included in the
optional phase compensation circuit.
NOTE: For the 400 Hz option (AD2S34xZIO), in addition to
the phase shift compensation referred to above, an extra 3.8 de-
grees of phase lead should be induded to compensate for the
internal phase shift within the hybrid. For higher frequency op-
tions this extra lead is not necessary as the internal phase shift
does not affect the stated accuracy.
The signals are connected
ing convention:
The two signal ground wires from each resolver should be con-
nected at the SIGNAL
the coupling between the sine and cosine signals- For the same
reason it is also recommended
using individual
reference signals twisted separately-
See Figure 1 for the recommended
of the three supply pins to GND.
The pin marked GND is connected
Pin 12 the LSB. Please see terminal connections
to each resolver and via an optional phase shift compensation
for suitable phase compensation
CONNECTING
The
should be -+15 V dc and -15 V dc, respectively,
be reversed, The voltage applied to V
nally. It is suggested that a parallel combination
(ceramic) and a 6,8 J.LF(tantalum)
should be taken to the zero volt pmenrial in the system.
power
supply
twisted pair cables with the sine, cosine and
Ecos
ESJS =- ERLO-RffJ sin u'( sill H
THE CONVERTER
voltages
SOLA
siCa
GND pin of the converter
DB"
D8"
08"
08..
=- ERJ.o-RlfJ sill {,j(cas II
P6.
DB,
08,
08.
06,
DB,
08,
08,
06,
to sin and CDSaccording to the follow-
connected
thar [he resolvers are connected
circuits.
capacitor
connection
electrically
L
to + V sand
should be
be placed from each
circuit.
to the case and
of a 100 nF
diagram.
AD2S34
and must not
to minimize
;
-
5 V nomi.
V spins