3
Signet 8250-2 Level Transmitter
4.2 Serial Data Connections
• The Input/Output terminals on the 8250 carry S
3
L serial data from the 2450 Pressure Sensor or from the 2250 Level Sensor and
from the External Relay Module.
• You MUST reset sensor con
fi
guration (see Calibrate menu) for all new systems and after connecting a new sensor or relay module
to the I/O terminals.
• Do not route sensor or output cables in conduit containing AC power wiring. Electrical noise may interfere with sensor signal.
• Routing cable in grounded metal conduit will help prevent electrical noise and mechanical damage.
• Seal cable entry points to prevent moisture damage.
• Only one wire should be inserted into a terminal. Splice double wires outside the terminal.
• The
TOTAL
cable length from I/O devices to the transmitter must not exceed 122 m (400 ft.).
• For best performance, ground the sensor SHIELD wire to a local earth ground at a point near the sensor.
• Consult the sensor manual for additional wiring information.
4.1 System Power/Loop Connections
-
+
4
3
2
1
4
3
2
1
-
+
4
3
2
1
+
-
+
-
-
+
4
3
2
1
4
3
2
1
4
3
2
1
+
-
-
+
-
+
4
3
2
1
4
3
2
1
4
3
2
1
4
3
2
1
Channel 1
4 to 20 mA in
Channel 2
4 to 20 mA in
System Pwr Loop -
System Pwr Loop +
AUX Power -
AUX Power +
System Pwr Loop -
System Pwr Loop +
AUX Power -
AUX Power +
Loop Input
4 to 20 mA
System Pwr Loop -
System Pwr Loop +
AUX Power -
AUX Power +
Loop Input
4 to 20 mA
System Pwr Loop -
System Pwr Loop +
AUX Power -
AUX Power +
System Pwr Loop -
System Pwr Loop +
AUX Power -
AUX Power +
Example: Two transmitters connected to PLC/Recorder with separate power supply
PLC or Recorder
Transmitter 1
Terminals
Transmitter 2
Terminals
Power
Supply
12 to 24 VDC
* See AUX POWER Note
Connection to a PLC with built-in power supply
Internal
PLC Connection
Power
Supply
12 to 24 VDC
PLC Terminals
Transmitter
Terminals
* See AUX POWER Note
Connection to a PLC/Recorder, separate supply
PLC or Recorder
Transmitter
Terminals
Power
Supply
12 to 24 VDC
* See AUX POWER Note
Stand-alone application, no current loop used
Transmitter
Terminals
Power
Supply
12 to 24 VDC
* See AUX POWER Note
Note:
AUXILIARY power
is required to operate the relays.
13
12
11
8059 External
Relay Module
2450 Pressure Sensor
8250 I/O
Terminals
Shield (Gnd)
Red (I/O)
Black (V+)
The TOTAL cable length connected to the 8250
input/output terminals must not exceed 122 m (400 ft)
The External Relay Module provides
“Pass-Thru” terminals to connect the
sensor in series via S
3
L.
2250 Level Sensor
OR
