Smithy Ez-Trol2 - Manual (Page 15)

BASIC ELECTRICAL COMPONENTS AND ITS FUNCTIONS
1. Motherboard – Chosen specifically to handle the real time requirements of CNC control pro-
grams for our machines, it has the connections for the keyboard and mouse, plus a D-subminiature
type VGA connection for the monitor. The motherboard uses conductive polymer solid capacitors
for durabilty and long life. Intel 45nm CPU chips provide dual core capabilities while using 35% less
power. Along with the power savings of a solid state disk, this system delivers a high performance
computer using a small power supply and generates less waste heat.
Figure 4.3 EZ-Trol II Motherboard
2. MESA Electronics 5I20 Card – A field programmable gate array card that is programmed gen-
erate step pulses, spindle speed control signals, and provide general pupose I/O. It delivers superi-
or quality motion control at high speeds, and makes the graphical user interface more responsive.
This also frees up the main CPU for work on lower frequency but computationally intensive tasks
like trajectory and kinematics calculations. Connecting this outboard “helper chip” to the main
CPU through the high speed, low latency PCI bus back plane delivers better performance than sim-
ilar systems that use USB, serial port, or Ethernet connections.
3. Compact Flash Card Adaptor – The control system software runs from a solid state disk (com-
pact flash) which greatly reduces power consumption and increases reliability by eliminating mov-
ing parts. The CF card simplifies upgrades by allowing the simple exchange of the existing card with
a new card holding file upgrades.
4. DC to DC Converter Power Supply – Converts the 24Vdc control system logic voltage to the
voltages required by the motherboard and CPU. This eliminates the standard PC power supply as a
source of trouble. This power converter has been designed for operation in automotive and indus-
trial environments and simplifies the system power distribution.
5. Isolated I/O Boards – Converts the TTL signals from the MESA S120 Board into 24 Volt com-
patible I/O. All timing critical electrical signals, and all signals that require high fidelity data trans-
mission for proper circuit operation are transmitted in “differential” form over two wire twisted
pair circuits, rather than the typical one wire plus ground “single ended” circuits.
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