User`s guide

Appendix C Using the Digital Port
198 Model N6705 User’s Guide
Configuring the Digital Port
The following table describes the possible pin configurations for the
digital port functions. For a complete description of the electrical
characteristics of the digital port, refer to Appendix A.
Pin Function
Available configurable pins
Digital I/O and Digital In
Pins 1 through 7
External Trigger In/Out
Pins 1 through 7
Fault Out
Pins 1 and 2
Inhibit In
Pin 3
Output Couple
Pins 4 through 7
Common (⊥)
Pin 8
In addition to the configurable pin functions, the active signal
polarity for each pin is also configurable. When Positive polarity is
selected, a logical true signal is a voltage high at the pin. When
Negative polarity is selected, a logical true signal is a voltage low at
the pin.
Bi-directional Digital I/O
Each of the seven pins can be configured as general-purpose bi-
directional digital inputs and outputs. The ground reference for the
pins is Signal Common on pin 8. Bit assignments are as follows:
Pin
7
6
5
4
3
2
1
Bit weight
6 (msb)
5
4
3
2
1
0 (lsb)
The I/O pins can be used to control both relay circuits as well as
digital interface circuits, as illustrated in the following figure.
B) Digital Interface CircuitsA) Relay Circuits
TTL, AS, CMOS, HC
Relay driver
Pins 1 - 7
(contain internal
clamp diodes for
inductive flyback)
Coil
Current
0.1 A
Max.
16.5 V Max.
Digital Output
Pins 1 - 7
Digital Input
Pins 1 - 7
1 2 3 4 5 6 7
I
1 2 3 4 5 6 7
I
1 2 3 4 5 6 7
I