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Model T940 User Manual
Publication No. 980938 Rev. K
UR14 Driver/Receiver Board I-16
Astronics Test Systems
T940
DB
T940
UR14
T940 EXTERNAL PROBE MODULE
PROBE
RELAY
NO
NC
NODE
DETECT
CIRCUITRY
AC
COMPENSATION
DETECT
CIRCUITRY
PROBE DETECT
PROBE
POWER
+12V
-12V
PBUT
(AUX4 A)
PROBE MODE
PROBE_CAL
CVH
UR14 LOGIC
+3.3V
CBUS
PROBE_IN
PROBE OUT
(AUX1 A)
CVL
DVH
DVL
T940
SEQ A
LOGIC
PROBE
MEMORY
HIGH SPEED
AMPLIFIER
DUT_GND
9M
Ω
10pF
AC
COMPENSATION
CONNECT
SWITCH
CONNECT
LED
DUT_GND
+12V
-12V
PROBE COMP
(AUX2 A)
Figure I-10: External Probe Module
Signal Descriptions (Figure I-10)
EXTERNAL PROBE MODULE
is the external PCB assembly that is
connected to the UR14 via a cable providing; a high speed
buffer for probe data to the UR14, probe compensation
circuitry, contact detection circuitry, and PROBE and CAL
BNC connections.
PROBE COMP
AUX4 A Output to the external probe module to control the
contact detect relay. When not used with the probe it can
be used as an I/O signal.
PROBE OUT
Signal path that can be used to adjust the compensation of
the external probe. Note that this connection is not on the
probe connector.
PROBE IN
Input signal from the external probe. When not used with a
probe AUX1 A is a programmable level I/O signal.
PROBE CAL
Calibration output signal for the external probe. Supplies
compensation square wave and DC Calibration outputs.
When not used with a probe AUX2 A is a programmable
level I/O signal.
PROBE POWER Su12V and -12V to the external probe module.
PROBE MODE
This is a control signal from the Sequencer for support of
external probe operations.
PBUT
This is a Probe Button input signal to the Sequencer for
support of external probe operations.
DUT_GND
When PROBE DETECT is true this input is inactive. Any