Pin
Number
Label Description
Pin
Number
Label Description
65
Ch11Lo
Channel 11 Low
72
Ch24Hi
Channel 24 High
66
BHi
B-bus/Ch33 High 73
Ch25Hi
Channel 25 High
67
Ch14Hi
Channel 14 High 74
Ch27Hi
Channel 27 High
68
Ch16Hi
Channel 16 High 75
Ch29Hi
Channel 29 High
69
Ch18Hi
Channel 18 High 76
Ch31Hi
Channel 31 High
70
Ch20Hi
Channel 20 High 77
DHi
D-Bus/Ch35 High [1]
71
Ch22Hi
Channel 22 High 78
+5V
+5V unregulated supply
[1] D-Bus is not available when using an Isothermal Terminal Block (SMX40T).
Table 3-1. The Scanner’s DB-78 connector pin assignments.
ChxHi, ChxLo -
These are the channel positive and negative terminals for all group channels, respectively. It starts
with Ch1Hi/Lo and ends with Ch32Hi/Lo. Depending on the Scanner configuration, these lines are routed to the bus
terminals AHi/Lo, BHi/Lo, CHi/Lo, or DHi/Lo.
AHi, ALo -
These are the A-bus positive and negative terminals respectively. The channels positive and negative
lines may be routed to these lines depending on Scanner configuration. In the Universal mode, it is also possible to
route bus pairs to other bus pairs.
BHi, BLo -
These are the B-bus positive and negative terminals respectively. The channels positive and negative
lines may be routed to these lines depending on Scanner configuration. In the Universal mode, it is also possible to
route bus pairs to other bus pairs. In TwoWire mode these are also Ch33Hi/Ch33Lo lines.
CHi, CLo -
These are the C-bus positive and negative terminals respectively. The channels positive and negative
lines may be routed to these lines depending on Scanner configuration. In the Universal mode, it is also possible to
route bus pairs to other bus pairs. In TwoWire mode these are also Ch34Hi/Ch34Lo lines.
DHi, DLo -
These are the D-bus positive and negative terminals respectively. The channel positive and negative
lines may be routed to these lines depending on Scanner configuration. In the Universal mode, it is also possible to
route bus pairs to other bus pairs. It is important to note that when using the Isothermal Block the DHi and DLo
terminals should not be used, and a configuration involving them should not be selected with the exeption of the
ColdJunction
configuration which selects the Cold Junction temerature sensor of an SMX40T. Therefore
configurations such as
FourGroups
should not be used, and when selecting
Universal
configuration, care must be
taken not to include these terminals. Since these lines also serve as Ch35Hi/Ch35Lo, avoid selecting Ch35 when
using the Isothermal Block (SMX40T) In
TwoWire
mode.
TrigComm -
This is the
TrigIn
and
TrigOut
return terminal. Both of these signals are referenced to it. All three
signals associated with the trigger circuitry,
TrigComm
,
TrigIn,
and
TrigOut
are optically isolated from the rest of
the terminals in the DB-78 connector.
Signametrics
14