Keithley KPCI-3110, Руководство пользователя

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KPCI-3110 and KPCI-3116 User’s Manual Installation and Configuration 3-13
Wiring signals
This section describes how to wire signals to the STP-3110 screw terminal panel.
CAUTION To avoid electrical damage, ensure that power is turned off to the
computer and to any attached devices before wiring signals to the
STP-3110 screw terminal panel.
TIP
When first installing the board, try wiring a function generator or a
known voltage source to analog input channel 0 (use the differential
configuration), an oscilloscope or voltage meter to analog output chan-
nel 0, a digital input to digital I/O Port A, and an external clock or scope
to counter/timer channel 0. Then, run DriverLINX Analog I/O Panel to
verify that the board is operating properly. Once you have determined
that the board is operating properly, wire the signals according to your
application’s requirements.
Keep the following recommendations in mind when wiring signals to the STP-3110 screw termi-
nal panel:
•
Use individually shielded twisted-pair wire (size 14 to 26 AWG) when using the KPCI-3110
or KPCI-3116 board in high electrical noise environments.
• Separate power and signal lines by using physically different wiring paths or conduits.
•
To avoid noise, do not locate the STP-3110 screw terminal panel and cabling next to sources
that produce high electromagnetic fields, such as large electric motors, power lines, sole-
noids, and electric arcs, unless the signals are enclosed in a metal shield.
• Connect the analog shield to screw terminals TB35 and TB36, and to TB51 through TB56 on
the STP-3110 screw terminal panel.
•
Connect the digital shield to screw terminals TB105 and TB108 on the screw terminal panel.
• Connect the analog and digital shields to one end only (either at the STP-3110 or at the sig-
nal source).
Connecting analog input signals
The STP-3110 screw terminal panel supports both voltage and current loop inputs. You can con-
nect analog input voltage signals to the STP-3110 in the following configurations:
•
Single-ended — Choose this configuration when you want to measure high-level signals,
noise is not significant, the source of the input is close to the STP-3110 screw terminal panel,
and all the input signals are referred to the same common ground. When you choose the
single-ended configuration, all 32 analog input channels are available.
• Pseudo-Differential — Choose this configuration when noise or common-mode voltage
(the difference between the ground potentials of the signal source and the ground of the
STP-3110 screw terminal panel or between the grounds of other signals) exists and the
differential configuration is not suitable for your application. This option provides less noise
rejection than the differential configuration; however, all 32 analog input channels are
available.
•
Differential — Choose this configuration when you want to measure low-level signals (less
than 1V), you are using an A/D converter with high resolution (> 12 bits), noise is a signifi-
cant part of the signal, or common-mode voltage exists. When you choose the differential
configuration, 16 analog input channels are available.