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Technosoft 2022
15
iPOS4803 Microdrive EtherCAT Technical Reference
3.4.2.1
Motherboard PCB Design
It is recommended to use a multi-layer PCB for the motherboard, in order to have enough room for routing all the pins
of the iPOS4803P / iPOS4803PE drives. Using a 2-layer PCB is possible when some of the pins remain unconnected.
The iPOS4803P / iPOS4803PE drives are intended to be mounted on a mainboard. The recommended method of
electrical connection is to use sockets on the mainboard. It is also possible to directly solder the module into the
mainboard.
To secure the modules to the mainboard, it is recommended to have the mainboard equipped with 3 self-clinching nut
inserts, with internal thread M2. The inserts will allow to use 3 screws M2x10, which will pull the module into the
mainboard.
The recommended socket type, inserts and screws are:
Image
Connector
Description
Manufacturer
Part Number
J1
2x11, 2.0mm pass-through SMD socket
Lanbo electronics
PSDSM20-22G-24-PCH
J2
2x8, 2.0mm pass-through SMD socket
PSDSM20-16G-24-PCH
-
Self-clinching nuts M2
PennEngineering®
(PEM®)
KF2-M2-ET
-
Screws M2x10
Bossard
BN610-M2x10
The 3 fixing holes shall provide a means to pull the iPOS drive against the PCB. For example, use self-clinching nuts
pressed onto the PCB on the bottom side. The iPOS drive shall be pressed against the PCB using 3 screws M2x10,
with head diameter not larger than 5mm (such as hexsocket
head cap screws, colloquially also called “Inbus”).
The fixing hardware shall be connected to system ground (GND), to improve thermal dissipation and EMC emissions.
3.4.2.2
Recommendations for the PCB Design
Below is a list of recommendations for the PCB design of the motherboard:
•
Motor supply and motor outputs: use islands / areas of copper to escape connector area; this will maximize
current capability. When using simple tracks, use at least 100mil cross section (75mil track width for 1oz/ft
2
copper thickness)
–
for iPOS4803P / iPOS4803PE drives.
•
Motor supply and ground return tracks between iPOS4803P / iPOS4803PE drive and the nearby V
MOT
decoupling capacitor are to be considered as EMI sources, and kept to a minimum length.
•
Place the decoupling capacitors on V
MOT
and V
LOG
(see also 3.10 Power Supply Connection) as close as
physically possible to the drive, to minimize EM radiated emissions. For un-shielded applications (no metallic
box) and typical EMC regulations, the spacing between drive and capacitors must be less than 3
centimeters.
•
In multi-axis applications (multiple iPOS4803P / iPOS4803PE drives on the same motherboard), it is
preferable to have a separate decoupling capacitor for each drive’s V
MOT
. For V
LOG
it is acceptable to share
one decoupling capacitor for two drives.
•
For stringent EMI requirements, it may be necessary to add common-mode filtering on the motor and/or logic
supply inputs. Be sure to use 3-phase EMC filters, not 2-phase filters, in order to fulfill the basic requirement
of zero common-mode current through the filter. This is necessary because the ground negative return is
shared between V
MOT
and V
LOG
.
•
Motor outputs shall be routed with parallel traces, and minimizing the loop area between these tracks. Avoid
placing components above or below the motor output tracks, as these components may become effective
antennas radiating EMI. If possible, route all 3 motor outputs in strip-line configuration (above or below a
ground plane).
•
For stringent EMI requirements, it may be necessary to add common-mode inductors on the motor outputs.
Place these filters near the iPOS4803P / iPOS4803PE drive, not near the external connector, to reduce
radiation from the PCB tracks.
•
Motor outputs must be separated from any nearby track (on the same layer) by a guard ring / track / area
connected to ground. It is recommended to use the same guarding precaution also for tracks on nearby
layers, i.e. use intermediate guard layer(s) connected to ground. The motor outputs must be treated as first
source of noise on the motherboard. Second source of noise is the current flow between each drive
and it’s
decoupling V
MOT
capacitor.