AV6A 11
Parallel Outputs “L”
Parallel output encoders represent the encoder position within
one turn, and the number of turns using output wires for each
measurement bit.
Preferred cable: Nidec Avtron recommends structured cabling wiring
systems including overall shielding, available from a broad range of
vendors as well as Nidec-Avtron.
Number of
Nodes
1
Units
Max. Overall
Cable Length*
150
[50]
ft
[m]
*Note that maximum cabling length is a function of output resolution
per turn * RPM, cable capacitance, and voltage. To increase cable
length, decrease supply voltage or measurement resolution if possible.
NOTE: Standard Avtron absolute parallel encoders include preset/
zero function. For maximum speed of response, request a special
model with no reset/preset function. This increases the overall
output response by 10X.
Measuring Position, Speed, and Acceleration
To read position into your device (acceleration and speed
measurement is not supported.): Connect the power +V, 0V, and
output wires to the measuring PLC or device.
For multiturn & single turn encoders: position data provided as
little-endian (lowest bit = right-most bit). Single-turn data/data
within 1 turn is provided in the least-significant bits. Multiturn data
is provided directly “above” the single turn data, bitwise. Example:
8 bit turns x 12 bits/turn encoder, lowest 12 bits = position within
one turn, next 8 bits (up to bit 20) represent turns position data.
Zero Position for Multiturn Encoders & Single turn Encoders:
NOTE: Do not attempt to use zero/preset function while the encoder
is rotating. Doing so will produce unpredictable results.
To set zero position, raise the voltage level of the Preset input to +V
(supply of the encoder) for at least 0.1sec. The encoder will set the
outputs to zero.
Setting Direction of Rotation for Count Up/Down:
Setting the Complement/Direction input will control the direction of
counting:
Comp/Dir = 0, Counterclockwise rotation = count up
Comp/Dir = 1, Clockwise rotation = count up
(rotation as viewed from the back of the encoder)
Latching Counts:
Avtron parallel-bit encoders enable a latch input to hold the output
constant (typically for slower input systems to measure the output).
Latch = 0, no latching
Latch = 1, latched within 3uS of rising edge
PARALLEL TROUBLESHOOTING
Viewing on oscilliscope: The lowest significant bit can be monitored
as the encoder is rotated. As long as the rotation speed is low
enough where RPM/60 * counts/turn < maximum output frequency,
the output frequency can be measured and compared to the
expected RPM/60 * counts/turn. Example: 12bit/4096 count
encoder, turn at 60 RPM = 60/60 * 4096 = 4096Hz.
A digital state analyzer can also be connected to monitor some or all
of the encoder lines simultaneously.
If the position is changing as the encoder moves, but is reported
incorrectly, the zero/preset line may have been activated at the
wrong physical position of the machine. Drive the machine to the
home/preset position, and cycle power to see if the position is
correctly reloaded.
