SERIES PMC408 PCI MEZZANINE CARD 32-CHANNEL DIGITAL I/O MODULE
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CARD CAGE CONSIDERATIONS
Refer to the specifications for loading and power requirements.
Be sure that the system power supplies are able to accommodate
the power requirements of the carrier board, plus the installed IP
modules, within the voltage tolerances specified.
IMPORTANT
: Adequate air circulation must be provided to prevent
a temperature rise above the maximum operating temperature.
The dense packing of the PMC modules to the carrier/CPU
board restricts air flow within the card cage and is cause for
concern. Adequate air circulation must be provided to prevent a
temperature rise above the maximum operating temperature and to
prolong the life of the electronics. If the installation is in an industrial
environment and the board is exposed to environmental air, careful
consideration should be given to air-filtering.
BOARD CONFIGURATION
Power should be removed from the board when installing PMC
modules, cables, termination panels, and field wiring. Refer to
Mechanical Assembly Drawing 4501-859 and your PMC module
documentation for configuration and assembly instructions. Model
PMC408 I/O Boards have no jumpers or switches to configure--
interrupts are configured through software command.
CONNECTORS
Front Panel Field I/O Connector P1
The front panel connector P1 provides the field I/O interface
connections. The front panel connector is a SCSI-2 50-pin female
connector (AMP 787082-5 or equivalent) employing latch blocks and
30 micron gold in the mating area (per MIL-G-45204, Type II, Grade
C). Connects to Acromag termination panel 5025-552 from the front
panel via round shielded cable (Model 5028-187).
Front panel connector P1 pin assignments are shown in Table
2.1.
Table 2.1: PMC408 Field I/O Pin Connections P1
Pin
Description Number Pin
Description Number
OD00 1 OD25 32
OD01 2 OD26 33
OD02 3 OD27 34
OD03 4 OD28 36
OD04 6 OD29 37
OD05 7 OD30 38
OD06 8 OD31 39
OD07 9
Not Used
41
OD08 11
Not Used
42
OD09 12
Not Used
43
OD10 13
Not Used
44
OD11 14
Not Used
46
OD12 16
Not Used
47
OD13 17
Not Used
48
OD14 18
Not Used
49
OD15 19
COMMON
5
OD16 21
COMMON
10
OD17 22
COMMON
15
OD18 23
COMMON
20
OD19 24
COMMON
25
OD20 26
COMMON
30
OD21 27
COMMON
35
OD22 28
COMMON
40
OD23 29
COMMON
45
OD24 31
COMMON
50
I/O Noise and Grounding Considerations
The output channels of this model are the open drains of
mosfets with a common source connection. The PMC408 is non-
isolated between the logic and field I/O grounds since output
common is electrically connected to the PMC module ground.
Consequently, the field I/O connections are not isolated from the
carrier/CPU board and backplane. A copper ground plane foil has
been employed in the design of this model to help minimize the
effects of ground bounce, impedance drops, and switching
transients. However, care should be taken in designing installations
without isolation to avoid noise pickup and ground loops caused by
multiple ground connections.
This device is capable of switching many channels at high
currents. Additionally, the nature of the PMC interface is inherently
inductive. The outputs of this model are protected to voltages up to
60V. As such, when switching inductive loads, it is important that
careful consideration be given to the use of snubber devices to
shunt the reverse emf that develops when the current through an
inductor is interrupted. Filtering and bypassing at the load may also
be necessary. Additionally, proper grounding with thick conductors
is essential. Interface cabling and ground wiring should be kept as
short as possible. For outputs, the use of an interposing relay may
also be desireable for isolating the load, raising the drive capability,
or providing additional system protection. Please refer to Drawing
Drawing 4501-867 & 4501-868 for examples of these connections
and proper output and grounding connections.
Output Off-State Loading Considerations
With respect to output control, the 100K
Ω
input buffer current-
limiting resistors in combination with +4.7V voltage clamps will tend
to increase the off-state drain current with increased drain voltage
(up to 0.5mA at 60V). This is due to the fact that the input buffer
circuitry and output mosfet drain circuitry are connected in tandem to
the same I/O pin. If this presents a problem for your application,
then you should consider separating the inputs and outputs by using
multiple PMC408 modules.
PCI Local Bus Connector
The PMC408 module provides a 32-bit PCI interface to the
carrier/CPU via two 64 pin connectors. These connectors are 64-
pin female receptacle header (AMP 120527-1 or equivalent) which
mates to the male connector of the carrier/CPU board (AMP
120521-1 or equivalent). This provides excellent connection integrity
and utilizes gold-plating in the mating area. Threaded metric screws
and spacers are supplied with the PMC module to provide additional
stability for harsh environments (see Drawing 4501-859 for
assembly details). The pin assignments of the PCI local bus
connector are standard for all PMC modules according to the PCI
Mezzanine Card Specification (see Tables 2.2 and 2.3).
