Welch Allyn Atlas Service Manual page 97

P+12V
C211
.047uF
A
U205-3 3
+
P202-2
1
2
-
U205A
MC34072
C212
A
680pF
3
P202-5
4.4 Hardware Overpressure:
The output of the primary transducer is monitored for two overpressure conditions; pressures in excess of
13.3mmHg (nominal) and 314mmHg (nominal) are detected. These error conditions are transmitted to the
gate array on the CPU board, and if the error conditions are present for a long enough time period, a fault
message is displayed, and NIBP is disabled (see above for safety performance operation).
The output of the Primary Transducer drives the two comparators U203A/B. The comparison voltage is
derived through a resistor divider chain from a 5V regulator (U201). This regulator is the supply voltage
for the primary transducer, and sense the primary output is proportional to the supply voltage, tolerance
errors in the regulator are not critical.
L201
220uH
+12V P+12V
C229
+
10uF U201
78L05
8
IN OUT
A
C201
.047uF
A
A
Appendix A
Safety
Transducer
P202-Out+
P202
FPNS-07PGR
1
P+12V
+ -
6
P202-Out-
R220
806
5VRef
A
R221
Zero
3.16K
Offset
C213 R222
.01uF 1K
A A
P+5V
R201
576
1 U203-2
R202
P+12V
C202 174
+
4.7uF
U202-3 3
A
+
2
-
R203
3.32K
P+12V
R204
150
U202-5 5
+
6
-
C204 R205
.047uF 750
A A
P+12V
C216
.047uF
A
TP226
3
+
U206-1
1
2
-
U206A R223
MC34072 21.5K
A
U206-2
R224
1K
5
+
7 U206-7
6
-
U206B R225
MC34072 1K
A
P+12V
R226
21.5K
5
+
7 U205-7
6
-
U205B
MC34072
A
PrimaryPres
R206
1K
U203-3
C203 C222
.01uF
.047uF
A A
1
P+4.25V
U202A
MC34072 R209
1K
U203-5
A
U203-6
C223
.01uF
A
7
P+.75V
U202B
MC34072
A
10/14/99
R227
5.11K
SafetyPres
C214 C217
.047uF
.047uF
A
C215
.047uF
R207
+3.3V
464K
C205
P+12V
R208
.047uF 1.96K
A
3
+
1
NIBP-Overpressure
2
-
U203A
LM393
+3.3V
R210
A
464K
P+12V
R211
1.96K
5
+
7
NIBP-15mmHg
6
-
U203B
LM393
Over Pressure
Fault Circuit
A