
Chapter 4
Accessory and Cable Connections
©
National Instruments Corporation
4-7
NI 951x User Manual
Figure 4-6.
NI 9516 37-Pin Terminal Block Pin Assignments
Signal Connection Recommendations
This section contains detailed information about signal wiring including
precautions and guidelines for error-free operation.
General Connection Recommendations
Use the following guidelines when wiring signals and creating custom
cables:
•
Keep all signals and their ground connections wired separately from
the drive and encoder signal connections. Wiring these signals near
each other can cause faulty motion system operation due to signal
noise and crosstalk.
•
Use shielded cables with a low impedance connection to chassis
ground to minimize noise and signal crosstalk.
•
Use a separate power supply for the CompactRIO chassis and the
NI 951x module(s) to isolate the I/O from the controller.
•
Tie the V
sup
cable shield to chassis ground at the module side only.
•
Route wires along the machine frame to reduce high frequency noise.
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
GND
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
Forward Limit
Home
COM
Digital Input 0
Encoder 1 Phase B–
Encoder 0 Index+
Encoder 0 Index–
COM
+5V OUT
Position Compare
Reserved
Drive Command
†
Reserved
V
sup
†
Digital Input 1
†
Reserved
COM
†
Reserved
Shield
Reserved
Reverse Limit
Encoder 1 Phase A+
V
sup
Encoder 1 Phase A–
Encoder 1 Phase B+
Encoder 0 Phase A+
Encoder 0 Phase A–
Encoder 0 Phase B+
Position Capture
Encoder 0 Phase B–
Reserved
Drive Command COM
†
COM
†
Drive Enable
†
Reserved
Reserved
Reserved
Reserved
†
Indicates DSUB connector signals.