SERIES PMC230 PCI MEZZANINE CARD 16-BIT HIGH-DENSITY ANALOG OUTPUT MODULE
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Table 2.3: PMC230 Field I/O Pin Connections for P1
Pin Description
Number
Pin Description
Number
+CH00 1
COMMON
1
26
-CH00
1
2
COMMON
1
27
COMMON
1
3 COMMON
1
28
+CH01 4
COMMON
1
29
-CH01
1
5
COMMON
1
30
COMMON
1
6 COMMON
1
31
+CH02 7
COMMON
1
32
-CH02
1
8
COMMON
1
33
COMMON
1
9 COMMON
1
34
+CH03 10
COMMON
1
35
-CH03
1
11
COMMON
1
36
COMMON
1
12 COMMON
1
37
+CH04 13
COMMON
1
38
-CH04
1
14
COMMON
1
39
COMMON
1
15 COMMON
1
40
+CH05 16
COMMON
1
41
-CH05
1
17
COMMON
1
42
COMMON
1
18 COMMON
1
43
+CH06 19
COMMON
1
44
-CH06
1
20
COMMON
1
45
COMMON
1
21 COMMON
1
46
+CH07 22
COMMON
1
47
-CH07
1
23
COMMON
1
48
COMMON
1
24
EXT
TRIGGER*
49
COMMON
1
25 SHIELD 50
Notes:
1. The minus leads of all channels are connected to analog
common on the module.
Analog Outputs: Noise and Grounding Considerations
All output channels are referenced to analog common on the
module (See Drawing 4501-864 for analog output connections), but
each channel has a separate return (minus lead) to maintain
accuracy and reduce noise. Still, the accuracy of the voltage output
depends on the amount of current loading (impedance of the load)
and the length (impedance) of the cabling. High impedance loads
(e.g. loads > 100K
Ω
) provide the best accuracy. For low impedance
loads, the PMC230 can source up to 5mA, but the effects of source
and cabling resistance should be considered.
Output common is electrically connected to the PMC module
analog ground which connects to logic ground of the module at the
DAC’s. As such, the PMC230 is non-isolated between the logic and
field I/O grounds. Consequently, the field I/O connections are not
isolated from the carrier/CPU board and backplane. Care should be
taken in designing installations without isolation to avoid noise pickup
and ground loops caused by multiple ground connections. This is
particularly important for analog outputs when a high level of
accuracy/resolution is needed. Refer to Drawing 4501-864 for
example output and grounding connections.
External Trigger Input/Output
The external trigger signal on pin 49 of the P1 connector can be
programmed to accept a TTL compatible external trigger input
signal, or output hardware timer generated triggers to allow
synchronization of multiple PMC230 modules.
As an input, the external trigger must be a 5 Volt logic, TTL-
compatible, debounced signal referenced to analog common. The
trigger pulse must be low for a minimum of 125n seconds to
guarantee acquisition. It must not stay low for more than 6
μ
seconds, or additional, unwanted conversions may be triggered.
The actual conversion is triggered within 6.25
μ
seconds of the
falling edge of the external trigger signal. This type of conversion
triggering can be used to synchronize generation of analog output
signals to external events.
As an output an active-low TTL signal can be driven to additional
PMC230s, thus providing a means to synchronize the conversions
of multiple PMC230s. The additional PMC230s must program their
external trigger for signal input and convert on external trigger only
mode. The trigger pulse generated is low for typically 125n
seconds. See section 3.0 for programming details to make use of
this signal.
PCI Local Bus Connector
The PMC230 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 2.4 and 2.5).
Table 2.4: PMC Connector Pin Assignments for J1 (32-bit PCI)
Signal Name
Pin #
Signal Name
Pin #
TCK
1 -12V 2
GND 3 INTA# 4
INTB#
5
INTC#
6
BUSMODE1# 7
+5V
8
INTD#
9
PCI-RSVD*
10
GND 11
PCI-RSVD*
12
CLK 13 GND 14
GND 15
GNT#
16
REQ#
17 +5V 18
V(I/O)
19 AD[31] 20
AD[28] 21 AD[27] 22
AD[25] 23 GND 24
GND 25
C/BE[3]#
26
AD[22] 27 AD[21] 28
AD[19] 29 +5V 30
V(I/O)
31 AD[17] 32
FRAME# 33 GND 34
GND 35 IRDY# 36
DEVSEL# 37
+5V
38
GND 39
LOCK#
40
SDONE#
41
SBO#
42
PAR 43 GND 44
V(I/O)
45 AD[15] 46
AD[12] 47 AD[11] 48
AD[09] 49 +5V 50
GND 51
C/BE[0]#
52
AD[06] 53 AD[05] 54
AD[04] 55 GND 56
V(I/O)
57 AD[03] 58
AD[02] 59 AD[01] 60
AD[00] 61 +5V 62
GND 63
REQ64#
64
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