2-10
Functional Description
KPCI-3110 and KPCI-3116 User’s Manual
The conversion rate of each channel is determined by the frequency of the A/D sample clock.
Refer to
page 2-6
for more information on the A/D sample clock. The conversion rate of each
scan is determined by the period between external retriggers; therefore, it cannot be accurately
controlled. The board ignores external triggers that occur while it is acquiring data. Only exter-
nal retrigger events that occur when the board is waiting for a retrigger are detected and acted
on.
To select externally-retriggered scan mode, use software to specify the following parameters:
•
The dataflow as continuous (post-trigger).
•
Triggered scan mode as enabled.
•
The retrigger mode as an external retrigger.
•
The number of times to scan per trigger or retrigger (also called the multiscan count).
•
The retrigger source as the external digital (TTL) trigger or an external analog threshold
trigger.
Triggers
A trigger is an event that occurs based on a specified set of conditions. KPCI-3110 and
KPCI-3116 boards support a number of trigger sources and trigger acquisition modes, described
in the following subsections.
Trigger sources
KPCI-3110 and KPCI-3116 boards support the following trigger sources:
•
Software trigger
•
External digital (TTL) trigger
•
Analog threshold trigger
This subsection describes these trigger sources in more detail.
Software trigger
A software trigger event occurs when you start the analog input operation (the computer issues a
write to the board to begin conversions). Specify the software trigger source in software.
External digital (TTL) trigger
For analog input operations, an external digital trigger event occurs when the KPCI-3110 or
KPCI-3116 board detects either a rising or falling edge on the external A/D TTL trigger input
signal connected to screw terminal 77 on the STP-3110 screw terminal panel (pin 6 of connector
J2). The trigger signal is TTL-compatible.
Using software, specify the trigger source as a rising-edge external digital trigger or a falling-
edge external digital trigger.
Analog threshold trigger
For analog input operations, an analog trigger event occurs when the KPCI-3110 or KPCI-3116
detects a transition from above a threshold level to below a threshold level (falling edge), or a
transition from below a threshold level to above a threshold level (rising edge). The following
analog threshold trigger sources are available:
•
External Analog Trigger input signal
is
connected to screw terminal TB107 (Analog
Trigger) on the STP-3110 screw terminal panel (pin 34 on connector J2). Using software,
Summary of Contents for KPCI-3110
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Page 16: ...Preface...
Page 20: ...1 Overview...
Page 25: ...2 Functional Description...
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Page 61: ...3 Installation and Configuration...
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Page 86: ...4 Testing the Board...
Page 89: ...5 Calibration...
Page 92: ...6 Troubleshooting...
Page 99: ...A Specifications...
Page 111: ...B Connector Pin Assignments...
Page 116: ...C Systematic Problem Isolation...
Page 143: ...D Using Your Own Screw Terminal Panel...
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