Appendix A
Specifications
©
National Instruments Corporation
A-3
NI 951x User Manual
Motion I/O
Encoder 0 and 1 Phase A/B and Encoder 0 Index inputs
Type ................................................ RS-422 differential or
single-ended inputs
Digital logic levels, single-ended
Voltage..................................... –0.25 to 5.25 V
High, V
IH
................................. 2.0 V min
Low, V
IL
.................................. 0.8 V max
Digital logic levels, differential (Phase(+) – Phase(–))
Input high range....................... 300 mV to 5 V
Input low range ........................ –300 mV to –5 V
Common-mode voltage
1
.......... –7 to 12 V
Input current at 5 V ......................... ±1 mA
Min pulse width
2
Differential............................... 100 ns
Single-ended ............................ 400 ns
Max count rate
Differential............................... 20
×
10
6
counts/sec
Single-ended ............................ 5
×
10
6
counts/sec
Forward, reverse, and home inputs
Input type ........................................ Programmable: sinking or
sourcing
Digital logic levels, OFF state
Input voltage ............................
≤
5 V
Input current ............................
≤
250
μ
A
Digital logic levels, ON state
Input voltage ............................ 11 to 30 V
Input current ............................
≥
2 mA
Input impedance.............................. 30 k
Ω
± 5%
Min pulse width
2
............................. 100 µs
1
Common-mode voltage is the average of Phase+ and Phase–.
2
Assumes the minimum filter setting. Refer to the
NI SoftMotion Module
book of the
LabVIEW Help
for more information
about filter options.