NI ISM-7400 User Manual
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© National Instruments
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11
Figure 16.
Driving a Relay
Using the Optional Encoder
There are three versions of the NI ISM-7400: the NI ISM-7400 has a single shaft, the
ISM-7400D has a dual shaft, and the ISM-7400E has a dual shaft with a 1000-line, incremental
encoder assembled to the rear shaft of the unit. The A, B, and Index (Z) channel signals of this
encoder can be connected to the external controller for position verification and enhanced
performance. To facilitate connecting the encoder signals to your external controller, you should
purchase cable part number 748995-01.
Note
Maximum noise immunity is achieved when the differential receiver is
terminated with a 110
Ω
resistor in series with a 0.0047
μ
F capacitor placed across
each differential pair. The capacitor simply conserves power; otherwise power
consumption would increase by approximately 20 mA per pair, or 60 mA for 3 pairs.
Note
If making your own cable to connect the encoder signals to your controller,
NI recommends using a shielded cable with four or five twisted pairs for improved
noise immunity.
Figure 17.
NI ISM-7400 Encoder Connector