Series 3700A Switch and Control Cards Reference Manual
Section 13: Model 3750 multifunction control card
3700AS-909-01 Rev. A / Preliminary
13-19
Latching values
Channels support a status/state concept. The status of a channel indicates what conditions are
present on that channel at that point in time. Examples of channel status are:
•
An overload condition exists on that channel
•
A channel is presently matching a pre-determined match condition
•
The counter/totalizer channel’s count has overflowed.
To read the present status of a channel, send:
status_now = channel.getstate('1001')
If the digital I/O matches a present match value, the
status_now
value would be
channel.IND_MATCH
.
Status latching builds on this so that the status read by
channel.getstate()
remembers what has
happened. For example, status latching tracks if the condition EVER happened since its last reset so
that you know that the status occurred but is not now present. Manipulating the status so that it either
latches or not is accomplished with the following commands:
channel.setstatelatch()
channel.resetstatelatch()
The setting of the state latch can be read using
channel.getstate()
.
Power consumption implications
The Model 3750 draws a significant amount of power from the Model 3706 mainframe in order to
perform all of its functions. In cases where multiple Model 3750 cards are used, it is possible that not
all Model 3750 functions can be executed at the same time. The Model 3706 mainframe keeps track
of power requirements in real time and provides a notification if a power limit has been exceeded.
This notification is in the form of one or more error messages.
See
Power budgeting and calculation
(on page 3-2) for more information.
While operating the Model 3750, if a requested operation would consume an amount of power that is
not available, one of the following errors is generated:
•
#5513 "Not enough total power to complete requested card operation."
•
#5514 "Not enough bank power to complete requested card operation."
•
#5515 "Not enough slot power to complete requested card operation."
These errors mean that there was not enough available reserve power to complete the requested
operation on a total, bank, and slot basis, respectively. As a result, the requested operation would not
have been performed. To perform the requested operation, more available reserve power is needed
as described in
Options for working with power consumption limitations
(on page 13-20).
