HOT LINE
®
Blood and Fluid Warmer
Technical Service Pack
24
S E C T I O N 3
T e c h n i c a l D e s c r i p t i o n
Following signal
X
onto the next page, we see that it reaches
U4.4. U4 is an LP339 - a low-power version of an industry standard
quad comparator with open-collector outputs. Taking signal
X
high
turns on U4.4’s output, which starves darlington driver U3.5’s input
of current. This
was
being held on by R03/7, but now it turns off, so
cutting off the relay K1, which in turn removes power from the
pump motor and heater mains circuits, thereby rendering the
HOTLINE® (and any patients it may be attached to) safe.
This arrangement of open-collector devices feeding a
common input effectively creates an OR-gate, allowing multiple
inputs to control the output relay.
Float
Switch
Float
System
Normal
Interlock
Switch
Interlock
Overtemp
J3
J2
U4.2
U4.1
U4.3
U4.4
Relay
K1
U3.3
Piezo
U3.2
U3.4
U3.5
U2.4
S
X
AA
10
VU
15
12
3
R305
100k
R03/7
15k
R03/1
15k
R03/2
15k
R302
8.2M
R307
15.4k
R301
722R
R02/2
15k
R02/3
15k
R01/2
15k
R03/6
15k
R03/9
15k
R304
100k
R308
15.4k
R306
15.4k
CR302 Red
CR301 Red
CR303 Red
R 2
270R
CR 401
Green
R401
1k
C302
10 F
µ
C301
0.1 F
µ
3
2
14
4
13
6
5
12
7
10
11
12
13
5
9
8
12
3
3
1
1
2
2
2
4
15
14
13
8
14
9
1
GM-HL90_8308-A
Figure 3 - 5: HOTLINE
®
Thermistor Loss Alarm
Summary of Contents for level 1 HOTLINE HL-90
Page 1: ......
Page 14: ...Introduction Specifications Blood and Fluid Warmer ...
Page 20: ...Sub Assemblies Blood and Fluid Warmer ...
Page 28: ...Technical Description Blood and Fluid Warmer ...
Page 45: ...Disassembly Procedures Blood and Fluid Warmer ...
Page 58: ...Blood and Fluid Warmer Maintenance Testing and Calibration ...
Page 83: ...Troubleshooting Blood and Fluid Warmer ...
Page 88: ...Spare Parts Blood and Fluid Warmer ...
Page 96: ...Rounding Off Blood and Fluid Warmer ...
Page 106: ...Appendix 1 Circuits Blood and Fluid Warmer ...
Page 110: ...Appendix 2 PCB Layout Blood and Fluid Warmer ...
Page 115: ...Appendix 3 Symbols Glossary Blood and Fluid Warmer ...
Page 118: ...Appendix 4 Frequently Asked Questions Information Bulletins Blood and Fluid Warmer ...
Page 132: ...Ndjg CdiZh 9 V gVbh ...