5
2850 Conductivity/Resistivity Sensor Electronics
4 to 20 mA Wiring
Digital (S
3
L) Wiring
Dual Digital (S
3
L) Input Wiring
Dual Input is available on Digital (S
3
L) output
model 3-2850-63 only, for use with the Signet
8900 Multi-Parameter Controller.
Sensors may be the same or different cell
constants.
If the Dual Input model is used with a single
sensor, connect the sensor to Input 1 and set
all of the Input 2 switches to OFF (OPEN).
The Digital (S
3
L) output is compatible with the
Signet 8900 Multi-Parameter Controller and
the Signet 9900 Transmitter.
Refer to the wiring sections of the 8900 or 9900
manual to determine cable length limitations.
IMPORTANT: Provide Earth Ground as
indicated by
symbol.
Maximum length of 4 to 20 mA loop is 300 meters (1000 ft)
SW1
D3
1
2
3
1
2
3
4
ON
CTS
1
2
3
4
ON
CTS
4 20
V-
V+
Temp. IN
(WHITE)
Sensr Gnd
(SHIELD)
Signal IN
(RED)
Signal RTN
(BLK)
9 VDC
to
26 VDC
4-20 mA Loop Output
SW1
D3
1
2
3
1
2
3
4
ON
CTS
3-8900.621C
I/O Module 3-8900.401-X
1
2
3
4
5
6
7
8
9
10
11
12
13
14
+5VDC (Black)
Freq. Input (Red)
GND (Shield)
+5VDC (Black)
Freq. Input 2 (Red)
S L (Red)
GND (White/Shield)
+5VDC (Black)
S L (Red)
GND (White/Shield)
3
3
Analog Output 1
Analog Output 2
(if applicable)
(if applicable)
Frequency
Input
1
Frequency
Input 2
OR
S3L
Input
2
S3L
Input
1
+
-
+
-
V+
DA
T
A
GND
SHLD
V+
DC Power
Loop V
oltage
3-9900.395
H COMM Module
Gnd
Data
Temp. IN
(WHITE)
Sensr Gnd
(SHIELD)
Signal IN
(RED)
Signal RTN
(BLK)
Black
Red
White
9900 S
3
L Input
SW1
D3
1
2
3
1
2
3
4
ON
CTS
1
2
3
4
ON
CTS
V+
3-8900.621C
I/O Module 3-8900.401-X
1
2
3
4
5
6
7
8
9
10
11
12
13
14
+5VDC (Black)
Freq. Input (Red)
GND (Shield)
+5VDC (Black)
Freq. Input 2 (Red)
S L (Red)
GND (White/Shield)
+5VDC (Black)
S L (Red)
GND (White/Shield)
3
3
Analog Output 1
Analog Output 2
(if applicable)
(if applicable)
Frequency
Input
1
Frequency
Input 2
OR
S3L
Input
2
S3L
Input
1
+
-
+
-
Gnd
Data
Input 1
Input 2
Sensor 1
Sensor 2
Note:
The 2819-2823 and 2839-2842 sensors can
connect directly to the 9900 via the 9900's
optional Direct Conductivity/Resistivity
Module 3-9900.394 (159 001 699).
Dual Input applications usually include one sensor with a smaller cell constant and
one sensor with a larger cell constant.
Place the larger cell constant on Input 1.
This allows periodic recalibration of the larger cell by simply turning Input 2 OFF (OPEN).
IMPORTANT
: Provide Earth Ground as indicated by
symbol.
