TDT ACO32 Application guide

ACO32/ACO64 Motorized
Commutators
Hardware Reference
Updated 2022-10-31

© 2016-2022 Tucker-Davis Technologies, Inc. (TDT). All rights reserved.
Tucker-Davis Technologies
11930 Research Circle
Alachua, FL 32615 USA
Phone: [phone]
Fax: [phone]
Notices
The information contained in this document is provided "as is," and is subject to being changed,
without notice. TDT shall not be liable for errors or damages in connection with the furnishing, use, or
performance of this document or of any information contained herein.
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ACO32/ACO64 Motorized Commutators | 2

Table of Contents
ACO32/ACO64 Motorized Commutators
4Overview
5Power and Interface
5ACO32 Hardware Setup
6ACO64 Hardware Setup
7Features
7LEDs
7Manual Rotational Buttons
7Inhibit BNC
7External Ground
8Headstage Connections
9Amplier Connections
9Fiber Optic Rotary Joint
9Replacing the Optical Fiber (ACO32)
13Change Kits
14Replacing the Optical Fiber (ACO64)
17ACO Technical Specications
18ACO32 Dimensions
19ACO64 Dimensions
19Interface Receptacles
20ACO32 and ACO64 Amplier Connector Pinout
Table of Contents | 3

ACO32/ACO64 Motorized Commutators
Overview
The ACO32 and ACO64 (Active Commutator with Optogenetic stimulation) are motorized
commutators that actively track rotation on a headstage cable connected to an awake,
behaving subject. They spin the motor to compensate, eliminating turn-induced torque at the
subject's end of the cable. The commutator is typically used for systems acquiring neural
recordings from up to 32 or 64 channels when using a PZ5 analog amplier or up to 256
channels or 512 channels when using ZD digital headstages and a PZ5 digital amplier.
Built-in electrical shielding ensures an ultra-quiet environment for recording and lightweight
cables and connectors minimize the torque caused by subject motion. Pushbuttons allow for
optional manual control of the commutator motor, and an input BNC can be used to inhibit the
motor during critical recording periods. A banana jack provides access to ground, so that users
can connect the commutator ground to an external ground, such as a Faraday cage, to
minimize ground loops.
ACO32/ACO64 Motorized Commutators | 4

Optionally, a ber optic rotary joint with single-channel optical ber assembly may be added
(shown above) to allow optical targeting and excitation on neural circuits for artifact free
stimulation. The optical assembly is user serviceable to allow for easy optical ber
replacement.
Part numbers:
ACO32 - 32 Channel Commutator
ACO64 - 64 Channel Commutator
FORJ - Fiber Optic Rotary Joint and Fiber Optic Cable
Power and Interface
The ACO32 has a rechargeable 1950 mAh Li-ion Battery. The ACO64 has a 3900 mAh battery.
A 6-9 V, 3A, center negative adapter (one provided) charges the device. Low battery status is
reported only by a decrease in rotational speed.
ACO32 Hardware Setup
The commutator is mounted above the subject. A PZ preamplier is connected to the DB26
connectors marked A and B on the face of the commutator. A headstage (with splice
connector) and a splice-to-splice adapter are connected to the interface receptacles on the
connector module. See Headstage Connections below for more information on this
connection.
See ACO32 Dimensions for mounting dimensions.
ACO32/ACO64 Motorized Commutators | 5

ACO64 Hardware Setup
The ACO64 commutator is analogous to the ACO32 and also typically mounted above the
subject. A PZ preamplier is connected to the DB26 connectors marked A, B, C, and D on the
face of the commutator. A headstage (with splice connector) and a splice-to-splice adapter are
connected to the interface receptacles on the connector module. See Headstage Connections
below for more information on this connection.
See ACO64 Dimensions for mounting dimensions.
The
motor
in
the
ACO32
commutator
is
attached
to
a
plate
designed
to
allow
it
to
be
disengaged
for
testing
and
troubleshooting
noise
issues.
The
plate
may
slide
out
of
normal
position
during
shipping
or
anytime
the
commutator is turned upside down.
If
the
motor
is
not
engaged,
you
can
turn
the
bottom
section
of
the
rotating
shaft,
but
the
rest
of
the
shaft
does
not follow.
To reengage the motor:
Hold the commutator with the faceplate up.
Grip one side of the commutator.
Bring the commutator down to thump the bottom corner with the heel of your palm, as shown below.
Note
1.
2.
3.
The
motor
in
the
ACO64
commutator
does
not
disengage
like
the
ACO32.
The
ACO64
has
an
additional
hardware
mount on the bottom, below the headstage receptacles, facing the subject.
Note
ACO32/ACO64 Motorized Commutators | 6

Features
LEDs
The four indicator LEDs on the front panel indicate power, the status of the Inhibit BNC input,
clockwise rotation and counterclockwise rotation.
Manual Rotational Buttons
The commutator features both clockwise and counterclockwise manual rotational buttons.
When pressed, these buttons will rotate the commutator at approximately 18 RPM. Pressing
either of these buttons also overrides the current rotational state of the commutator.
Inhibit BNC
During critical recording periods it may be necessary to prevent rotation to ensure signal
integrity. A logical low (0) on the Inhibit BNC will prohibit any rotation initiated by either the
sensors on the commutator or the manual rotational button.
External Ground
A banana jack located on the face (GND) provides connections to common ground on the
commutator.
The external ground is optional and should only be used in cases where the subject must
occasionally make contact with a metal surface that isn't tied to the animal ground, such as a
lever press. When contact is made, a ground loop is formed that temporarily adds extra noise
to the system. Grounding this metal surface directly to the TDT hardware removes this ground
loop at the cost of raising the overall noise oor a small amount.
A cable kit is provided to ensure cables used with the external ground are suitable for this use.
Each kit includes: one male banana plug to male banana plug pass through and one male
P Power (~0.5 Hz ash when on)
I Inhibit
Counterclockwise rotation
Clockwise rotation
ACO32/ACO64 Motorized Commutators | 7

banana plug to alligator clip pass through. These cables also include ferrite beads to remove
any potential RF noise that might travel through the cable. For best results position the ferrite
bead close to the source of the RF noise.
Headstage Connections
Two or four interface receptacles are positioned on the rotary interface module. The
receptacles are labeled to correspond to the DB26 connectors on the face. The ACO32 uses 'A'
and 'B' labels, the ACO64 uses 1 to 4 silver marks on the receptacles. TDT offers headstages
and connectors with a mate for these receptacles.
ACO32/ACO64 Motorized Commutators | 8

The diagram above shows the ACO32 connection for the A subset of channels:
from headstage (with SPL16 analog or SPL16-D digital connectors)
to splice-to-splice connector
to commutator receptacle
to amplier connection cable.
Channel numbers correspond to the amplier bank of channels to which the cable is
connected. For example, if the 'A' connector is connected to Bank 'A' on the PZ5 preamplier,
channels are numbered 1 - 16.
Amplier Connections
The ACO commutator interfaces with a PZ amplier via two or four DB26 connectors, 16
analog channels each) on the face. Adapter cables may also be used for connections to
Medusa Preamps.
See ACO Technical Specications for connector pinout.
Fiber Optic Rotary Joint
The ber optic rotary joint (FORJ) assembly is an available add-on component. It includes an
FC/FC optical ber connector accessible on the commutator face and a single channel optical
ber threaded through the module. The default ber optic cable included with the system is
200 um core diameter, 0.22 NA, with a 1.25 mm OD metal ferrule. FORJ is also compatible with
branched optical bers of up to four bundles in the ACO64.
Replacing the Optical Fiber (ACO32)
The FORJ assembly can be removed and re-installed by the user to replace the optical ber.
To remove a currently installed FORJ:
Use a 3/32" Allen hex driver to remove the two screws securing the ber optic rotary joint to
the commutator face.
•
•
•
•
1.
ACO32/ACO64 Motorized Commutators | 9

Use the hex driver to remove two screws securing the encoder clamping plates.
Carefully pull the FORJ away from the commutator face until the ber is free.
Disconnect the ber from the joint.
Replace the ber.
To install the FORJ:
Insert metal cannula end of ber into center of gear inside of ACO32.
2.
3.
4.
5.
1.
ACO32/ACO64 Motorized Commutators | 10

Slowly push ber through hole until the end appears among the wires on the other side of
the ACO32.
Using a pair of tweezers, carefully pull the end of the ber and insert it into the hole next to
the encoder.
Pull the end of the ber through the hole and insert it through the hole in the groove of the
connector module.
Leave enough slack in the section of ber between the encoder and connector modules to
match the loop of the other wires. A small lightweight tie can be loosely attached to hold the
ber adjacent to the wires.
2.
3.
4.
5.
ACO32/ACO64 Motorized Commutators | 11

Connect the FC/PC connector end of the ber to (the smaller section of) the ber optic
rotary joint.
Slowly pull all of the excess ber through the ACO32 until the FC/PC connector is inside the
ACO32 and the ber optic rotary joint plate can be attached to the ACO32 plate.
Attach the encoder clamping plates back onto the ACO32 shaft by tightening the two
screws.
The plate should be just below body of the ACO32 and the encoder body should sit snuggly
inside the lip of the clamping plates. Be careful not to pinch any wires or the ber as the
plates are tightened together.
6.
7.
8.
ACO32/ACO64 Motorized Commutators | 12

Change Kits
TDT provides two kits for users removing or adding a FORJ after initial purchase.
If you purchased the ACO32 or ACO64 without a FORJ and then add one, use the kit below to
mount the new optics to the ACO32 or ACO64 faceplate.
If you purchased the ACO32 or ACO64 with a FORJ and wish to remove it, use the kit below to
cover the opening where the FORJ was previously mounted.
If
a
FORJ
is
not
used,
the
through-hole
can
be
used
for
other
related
applications
(e.g.
uid
delivery
system).
Contact TDT for more details or assistance.
Note
ACO32/ACO64 Motorized Commutators | 13

Replacing the Optical Fiber (ACO64)
The FORJ assembly can be removed and re-installed by the user to replace the optical ber.
To remove a currently installed FORJ:
Use a 3/32" Allen Hex driver to remove the two screws securing the ber optic rotary joint to
the commutator face.
Use the hex driver to remove the two screws securing the encoder clamping plates.
Carefully pull the FORJ away from the commutator face until the ber is free.
The two congurations use different screws, so be sure to save all screws.
Note
1.
2.
3.
ACO32/ACO64 Motorized Commutators | 14

Disconnect the ber from the joint.
Replace the ber.
To install one optical ber in the FORJ:
Insert metal cannula end of the ber into center of gear inside the ACO64.
Slowly push ber through hole until the end appears among the wires on the other side of
the ACO64. Carefully pull the wire through the slip ring.
Insert and guide the ber through a hole in the encoder cover, then pull through.
4.
5.
1.
2.
3.
ACO32/ACO64 Motorized Commutators | 15

Secure the two encoder clamping shells back onto the ACO64 shaft by inserting and
tightening the two screws.
The plate should be just below the body of the ACO64 and the encoder body should sit
snugly inside the lip of the clamping plates. Be careful not to pinch any wires or the ber as
the plates are tightened together.
4.
5.
ACO32/ACO64 Motorized Commutators | 16

ACO Technical Specications
Channels ACO32 with analog PZ5 or PZA: up to 32 analog channels
ACO32 with digital PZ5 or PZD: up to 256 digital channels
ACO64 with analog PZ5 or PZA: up to 64 analog channels
ACO64 with digital PZ5 or PZD: up to 512 digital channels
Signal/Noise 120 dB (20 Hz to 25 kHz)
RPM (approx) 18
Digital Inputs 1 Inhibit
Power Consumption ACO32 and ACO64 quiescent: 35 mA
ACO32 rotating: 65 mA
ACO64 rotating: 75 mA
Run time ACO32: ~20 hr
ACO64: ~40 hr
Power Supply ACO32: 1950 mAh Li-ion battery. 1000 cycles of charging.
ACO64: 3900 mAh Li-ion battery. 1000 cycles of charging.
Charger 6-9 V, 3A, center negative.
Battery charges in 3-4 hours.
Mass ACO32: ~917g
ACO32 with FORJ: ~957g
ACO64: ~1372g
ACO64 with FORJ: ~1412g
ACO32/ACO64 Motorized Commutators | 17

ACO32 Dimensions
ACO32/ACO64 Motorized Commutators | 18

ACO64 Dimensions
Interface Receptacles
The interface receptacle diagram shows how the pins on each receptacle map to the pins on
the associated DB26 connector on the face of the commutator. See pinouts below for the
appropriate model.
ACO32/ACO64 Motorized Commutators | 19

Diagram reects pin numbers (not channel numbers).
For information on making custom connections to the commutator, see Tech Note TN0896.
ACO32 and ACO64 Amplier Connector Pinout
Connectors are labeled A and B on ACO32 and A, B, C, D on ACO64. Electrode channels below
are relative to the electrode/headstage connected to the corresponding interface receptacle.
ACO32/ACO64 Motorized Commutators | 20