User`s guide

60
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Operation Theory
4.5.2 Auxiliary Function Inputs (AFI)
Users can use the AFI in applications that take advantage of external cir-
cuitry to directly control the DAQ-2213/2214 cards. The AFI includes 2
categories of timing signals: one group is the dedicated input, and the other
is the Low-Cost input. Table 14 illustrates this categorization.
Summary of the auxiliary function input signals and the corresponding
functionalities
Category Timing signal Functionality Constraints
EXTTIMEBASE
Replace the
internal
TIMEBASE
1. TTL-compatible
2. 1MHz to 40MHz
3. Affects on both A/D
and D/A operations
EXTDTRIG
External digital
trigger input for
A/D operation
1. TTL-compatible
2. Minimum pulse
width = 20ns
3. Rising edge or falling
edge
Dedicated
input
EXTWFTRG
(for DAQ-2214)
External digital
trigger input for
D/A operation
1. TTL-compatible
2. Minimum pulse
width = 20ns
3. Rising edge or falling
edge
Replace the
internal
ADCONV
1. TTL-compatible
2. Minimum pulse
width = 20ns
3. Rising–edge sensi-
tive only
AFI[0]
(Dual functions)
Replace the
internal
SCAN_START
1. TTL-compatible
2. Minimum Pulse
width >
2/TIMEBASE
Multi-function
input
AFI[1]
(for DAQ-2214)
Replace the
internal DAWR
1. TTL-compatible
2. Minimum pulse
width = 20ns
3. Rising–edge sensi-
tive only
Table 14: Auxiliary function input signals and the corresponding
functionality