Tweco HMC-410 - Manual (Page 32)

HMC-410
2-14 July 27, 2005
2.10 Hardware Description
The HMC-410 is comprised of five major subassemblies.
Each subassembly provides a distinct function, and
understanding these functions can be helpful in
understanding the operation of the HMC- 410. The
subassemblies are:
1. Enclosure/Cabling
2. Control/Display Printed Circuit Board PCB Assembly.
3. Power Supply/Motor Control PCB Assembly
4. Controller PCB Assembly
5. Interface/Suppression PCB Assembly
These assemblies will be described in the following text.
Enclosure/Cabling
The enclosure and cabling will be the assembly that the
equipment operator will be in most constant contact with.
The enclosure provides the safe isolation between the
internal circuitry and the outside world. The cabling allows
the internal circuitry to communicate with itself, as well
as to the equipment outside of the enclosure.
The reason for the enclosure to isolate the circuitry is
twofold. First is to protect the operators from dangerous
signals which are present at various points inside the
panel. Second, the enclosure protects the internal circuitry
from damage and malfunction due to foreign objects and
external electrical emissions (noise). Both of these
functions are provided by having the whole chassis
electrically tied to earth ground. Because of this fact, it is
extremely critical that all chassis hardware is installed
when the panel is operating. The earth ground is provided
via the power source cable, pin G.
The enclosure also provides the operator with front panel
control of the panel. The power switch, toggle switches
(optional), control buttons, encoders, and displays are
all presented through the front panel. Care should be taken
to protect the front panel since many of these controls
are susceptible to damage.
The external cabling will interface the control with the
power source, wire feeder, a remote pendant (if present)
and user defined fixturing (as described in Rear Panel
Connections). The cabling is made of high durability
neoprene covering for long life. Care should be taken to
avoid damage to the cabling as that may cause safety
problems and possible damage to the equipment.
The cabling is shielded internally to limit susceptibility to
electrical noise. Keeping the cabling at a maximum
distance from electrical noisy devices (such as TIG
welders and high power lines) will also limit susceptibility
of the cabling (and the control) to noise.
The internal cabling interconnects the internal components
for proper operation of the control panel. Care has been
taken to choose interconnection systems that will provide
years of trouble-free operation. However, in cases of
jarring during shipping or use, it may be necessary to
occasionally re-seat these connectors.
Control/Display PCB Assembly
(Refer to Figure 2-6)
The Control/Display PCB (C/D Board) Assembly provides
the front panel controls and displays. It mounts directly
behind the front panel. Included on the C/D Board are the
numeric displays, light emitting diodes (LEDs), encoders
and pushbuttons. The C/D Board connects to the controller
board via a 26-position ribbon cable. The C/D Board
provides the controller board with encoder and button
status, and receives display data for the numeric and LED
displays.