Page1of 1
Filename: epc-g.tcw
Date: 12/20/97
By:R. Fenske
EPC-G
SCHEMATIC
10
9
8
+
-
LM324
U2
100K
R12
100K
R9
13
14
+
-
LM324
U3
Rx
20K
+12V
DISPLAYBOARD
GREENWIRE
OFPHONE
CABLEFROM
DISPLAYBD.
J2
R29
1M
1M
R15
0.1
uF
C2
12
28VAC
(RED)
GROUND
(GREEN)
28VAC
(WHITE)
100K
R13
12
13
14
+
-
LM324
U2
100K
R14
0.1uF
C4
POWERSUPPLYSECTIONS
ac
ac
-
+
7812
REG.
7912
REG.
1000uF
1000uF
C8
C10
C9
C11
C12
0.1uF
0.1uF
10uF
+12V#1FOR
EPCCIRCUIT#1
-12V
EPC2
GROUND
FROMAC
DISTRIBUTION
BOARD
BR1
BRIDGE
RECTIFIER
7812
REG.
C13
0.1uF
+12V#2FOR
EPCCIRCUIT#2
VR3
VR1
VR2
13
12
14
+
-
U4
LM324
10
9
8
+
-
LM324
U4
+12V
R25
10K
Q1
LT1004
+1.2VOUTPUT
-1.2VOUTPUT
R23
100K
100K
R24
EPCCIRCUIT #1
EPC-GCIRCUITBOARDLAYOUT
EPCCIRCUIT #2
POWERSUPPLY
R3
20K
+1.2V
-1.2V
P2
62K
62K
R4
3
2
1
+
-
LM324
U2
5
6
7
+
-
LM324
U2
J1
PHONEJACK
TOSENSOR
(ALLWIRES)
+1.2V
R1
1K
R
B
G
Y
2
3
6
+
-
U1
INA114
R2 3.3K P1 20K
5
6
7
+
-
LM324
U3
R8
1M
1K
R7
R5
1K
1K
R11
J3
J2
3
2
1
+
-
LM324
U3
R18
100K
R16
BLACKWIREOF
PHONECABLE
TODISPLAYBD.
"LED"
DISPLAY
BOARD
J2
D2
THEEPCBOARD
PROVIDESELECTRONIC
PRESSURECONTROL
OFGASESWITHINTHE
GASCHROMATOGRAPH.
ANEXTERNAL INPUT
(10mV/PSI) IS
NECESSARYFOR
COMPUTERCONTROL
OFTHEEPC.
THEREARETWO
IDENTICALCIRCUITS
ONTHISBOARD.
1M
R6
EPC-GPCB
SPAN
ADJUST
ZERO
OFFSET
ADJUST
R
B
Y
G
SCC100G
PRESSURE
SENSOR
8
1
RED
PHONE JACK
TOREGULATOR
BLACKWIRE
TOCHASSIS
GROUND
ADJ.
GND
100K
R10
R30
10K
C1
0.1
uF
D1
1N914
1K
R17
1K
1N914
SUMMINGCIRCUIT:
ADDSLOCALSETPOINT
ANDEXTERNAL INPUT
TOGETHERPRIORTO
THECOMPARATOR
CIRCUIT
PRESSURESENSOR
CIRCUIT:
DETERMINESACTUAL
PRESSURE
COMPARATOR
CIRCUIT:
LEDDRIVERCIRCUIT:
PROVIDESVISUAL
VERIFICATIONOF
EPCFUNCTIONS
REGULATORDRIVERCIRCUIT
29.5M
R31
-1.2V
J2
YELLOWWIREOF
PHONECABLE TO
DISPLAYBD.
"ACTUAL"
(PUSHBUTTON)
REDWIRE
OFPHONE
CABLETO
DISPLAYBD.
"TOTAL
SETPOINT"
(PUSHBUTTON)
EPC1
GROUND
5
EPC1
BOARD
GROUND
CHASSIS
GROUND
EPC2
BOARD
GROUND
2
R31=10M IFCARRIERPROGRAM
WIRE INA/DBOARDTP2
By:M.WATTS
Rev.Date:4/21/03
Q2
TIP100
+12V
GREEN
PORTERREGULATOR
G
50V
35V
35V
SPADELUG
"H"
JUMPER
FOR
STANDARD
EPC
CIRCUIT
ONLY
A/DTEST
POINT
SPADELUG
SETPOINTCIRCUIT:
USERADJUSTSTOSET
DESIREDPRESSURE
FORCARRIERTHIS ISA
GREEN/WHITEWIRE
SPADELUG
LOCALSETPOINT:
(PUSHBUTTON)
"P"
C
NO
NC
10M
EXTERNAL
INPUTFROM
A/DBOARD
(10mV=1PSI)
NOTEFOR
MULTIGAS#2ONLY.
"CARRIERLIMITTER"
CUTGREENWIREONPHONE
CABLEINHALF.RUNDISPLAY
SIDEOFGREENWIRETO
NORMALLYCLOSED(NC)SIDE
OFRELAY.RUNTHEEPC
BOARDSIDEOFTHEGREEN
WIRETOTHERELAYBOARD
COMMON(C) SIDEOFTHERELAY.
