National Instruments NI 1450 Series Manuale Utente
Chapter 4
Digital I/O Functionality
4-2
ni.com
TTL Inputs and Outputs
TTL is a fast-switching 5 V digital signaling standard commonly used
for applications that require high precision, such as camera triggering.
TTL inputs and outputs do not require a separate power supply.
for applications that require high precision, such as camera triggering.
TTL inputs and outputs do not require a separate power supply.
Caution
Do not connect voltage or current sources to TTL outputs. Doing so could
damage the NI 1450.
Table 4-1 summarizes the TTL inputs and outputs available on the NI 1450.
Isolated Inputs and Outputs
The isolated inputs and outputs on the NI 1450 have a separate ground
reference from the main NI 1450 supply, providing an easy means to
prevent ground loops that can introduce noise into a system. You can apply
signals up to 30 V to the isolated inputs. The voltage swing of the isolated
outputs is determined by the Viso you supply on the connector.
reference from the main NI 1450 supply, providing an easy means to
prevent ground loops that can introduce noise into a system. You can apply
signals up to 30 V to the isolated inputs. The voltage swing of the isolated
outputs is determined by the Viso you supply on the connector.
Table 4-2 summarizes the isolated inputs and outputs available on the
NI 1450.
NI 1450.
Table 4-1. TTL Inputs and Outputs
Primary
Function
Input or
Output
Number
Available
Signal Names
44-Pin DSUB
on NI 1450
Pin Number
37-Pin
Terminal Block
Pin Number
Trigger
Input
2
TTL Input 0
TTL Input 1
TTL Input 1
1
16
1
2
2
Timed Pulse
Output
6
TRIG 1, Pulse 5
TRIG 2, Pulse 6
TTL Output 1, Pulse 1
TTL Output 2, Pulse 2
TTL Output 3, Pulse 3
TTL Output 4, Pulse 4
TRIG 2, Pulse 6
TTL Output 1, Pulse 1
TTL Output 2, Pulse 2
TTL Output 3, Pulse 3
TTL Output 4, Pulse 4
—
—
—
4
6
7
6
7
18
—
—
—
5
7
8
7
8
20
Watchdog
Output
1
TTL Output 0
3
4
General-Purpose
Output
3
TTL Output 5
TTL Output 6
TTL Output 7
TTL Output 6
TTL Output 7
19
21
22
21
22
21
23
24
23
24