Dmm Bus - VTI Instruments Metek EX1202 User Manual

Reset Button
A reset button is accessible through a hole in the rear panel of the EX1200 and can be used to
restore default switch and network settings. This is useful for recovering from an incorrect or
unknown network configuration. There are three modes of operation for this button which are
based on the time the reset button is depressed. The reset is implemented according to the LXI
LAN Configuration Initialize (LCI) Mechanism specification.
Debounce Protection Mode
To prevent unintentional resets of the EX1200, there is a debounce protection mechanism. If the
reset button is depressed for less than 1 s, the activation of the reset button is treated as
unintentional and no action is taken.
Device Reset Mode
Depressing the button for a longer time (greater than 1 s but less than or equal to 10 s) causes the
EX1200 to reset in the same manner as clicking the Reset button on the browser interface. All
switch modules, for instance, will move their switches to the predefined "reset" state. There is no
LED indication for this reset mode.
Device Reboot/LCI Reset Mode
To perform an LCI reset and an immediate reboot of the EX1200, depress the reset button for
longer than 10 s, wait for the LAN LED to flash red, then release the button. This will return the
EX1200 to the power-on default state. The network configuration will be restored to factory
defaults in accordance with the LCI reset procedure described in the LXI Specification. The
EX1200 reverts to the default network configuration (DHCP and Auto IP enabled) instead of its
previous settings. VXI-11 Discovery (supported by the VISA IO-Libraries) can be used to
determine the IP address of the instrument.
DMM B
US
Some mainframes (EX1262, EX1266, EX1268, and EX1269) provide a five-line bus routed
through the backplane to the onboard DMM. The lines are analogous to the five front panel
banana-jack connections on the DMM (see Section 4). The bus is also accessible via the 9-pin rear
DMM BUS I/O connector which allows a signal to be routed to an external DMM or to extend the
bus to multiple mainframes.
Voltage and Resistance Measurements
CH1_COMH (Pin A15)
CH1_COML (Pin A14)
CH2_COMH (Pin E17)
CH2_COML (Pin E16)
+HI, -LO
+SHI, -SLO
+DAMPS
Figure 3-2 shows typical connections available through a switch module to the DMM bus on the
backplane. This direct backplane connection is not available on all cards (refer to the EX1200
Series Switch Card User's Manual for specific plug-in module capabilities). The DMM can be
configured to take readings through the front panel banana-jacks or the backplane bus
programmatically or through the SFP/browser interface of the DMM. Please see Section 4 for
more information on taking measurements with the DMM.
EX1200 Series Basic Mainframe Operation
K76
CH1_COMH (Pin A15)
CH1_COML (Pin A14)
K77
BPL_HI CH2_COMH (Pin E17)
BPL_LO CH2_COML (Pin E16)
Voltage and resistance measurements
Sense lines for 4-wire resistance measurements (used with +HI and -LO)
Current measurement (used with -LO)
F 3-2:T DMM B
IGURE YPICAL
4-Wire Resistance
K78
CH1_COMH (Pin A15)
CH1_COML (Pin A14)
K79
BPL_SHI CH2_COMH (Pin E17)
BPL_SLO CH2_COML (Pin E16)
C (EX1200-3072 S
US ONNECTIVITY
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Current Measurements (2 A Max)
K80
K81
BPL_DAMPS
BPL_LO
)
HOWN
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