Front Edge Connector Inputs And Outputs
•Svnchro Analog Inputs
Each channel has three synchro-analog inputs for inputting the angular value in synchro
format.
AC Reference Inputs
Each channel has an independent AC reference input (Ref HI and Ref LO) that provides
areference frequency for the 53A-571 that is equal to the frequency of the
synchro-analog inputs.
The polarity conventions for the synchro analog inputs and AC reference inputs are as
follows. Si, S2, and S3 are the synchro-analog inputs; RHI and RLO are the AC reference
inputs, high and low, respectively. 6 represents the position of the synchro shaft.
S3-SI = (RHI-RLO) sin 8
S2-S3 = (RHI-RL0) sin (8 +120°)
S1-S2 = (RHI-RL0) sin + 240°)
S3-S1 will be in phase with RH,-RLo when sin 6 is positive, and 180 degrees out of phase
with RH,-RL0 when sin 8 is negative.
S2-S3 will be in phase with RH,-RL0 when sin (0 + 120°) is positive, and 180 degrees out
of phase with R„,-RL0 when sin (8+ 120°) is negative.
S1-S2 will be in phase with RH,-RLO when sin (6+ 240°) is positive, and 180 degrees out
of phase with R,,,-RL0 when sin (8+ 240°) is negative.
DC Reference Out
The DC reference voltage output (+7.5V DC nominal) is used as the reference voltage
with respect to which the Error Out signal and the Velocity Out signal are measured.
CAUTION:
DC Reference Out should not be tied to ground.
Error Out
The Error Out signal, one line for each channel, is the filtered AC voltage measured by
sin (0 - 41). 8 is the actual synchro input angle, and (I) is the 16-bit digital angle
representing the current S/D converter output. A difference between angle 8 and angle
(I) reflects the tracking error between the instantaneous synchro input angle and the last
S/D conversion. The Error Out signal, a dynamic signal, is created when the 53A-571
digital output attempts to follow the analog input. Under static conditions, this error
output is zero. The Error Out signal is referenced to the 7.5V DC Reference signal. The
average signal amplitude at nominal input voltage (11.8V RMS) for +1 LSB of error
[equivalent to (0 -413) = 0.00551 is 16 mV RMS.
Velocity Out
The Velocity Out signal, one line for each channel, measures the rate of change of the
Error Out signal. A +I V DC output corresponds to a +0.5 rps (revolutions per second) rate
of change for 400 Hz units. The Velocity Out signal is measured with respect to the 7.5V
DC reference voltage.
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