Red Lion PAXT - Manual (Page 13)

13 13
+EX
C
-SIG.
-EXC.
+SIG.
+EXC.
COMM.
3 4
+SIG -SIG
6 5
4-Wire Bridge Input
3 4 5
+ -
- SI
G
+ SI
G
COMM
2-Wire Single
Ended Input
4 6 5 3
-EXC.
-SIG.
+SEN
+SIG.
+EX
C
-SIG +SIG COMM.
+EXC.
-SEN
6-Wire Bridge Input
DEADLOAD COMPENSATION
In some cases, the combined deadload and liveload output may exceed the
range of the 24 mV input. To use this range, the output of the bridge can be offset
a small amount by applying a fixed resistor across one arm of the bridge. This
shifts the electrical output of the bridge downward to within the operating range
of the meter. A 100 K ohm fixed resistor shifts the bridge output approximately
-10 mV (350 ohm bridge, 10 V excitation).
Connect the resistor between +SIG and -SIG. Use a metal film resistor with
a low temperature coefficient of resistance.
BRIDGE COMPLETION RESISTORS
For single strain gage applications, bridge completion resistors must be
employed externally to the meter. Only use metal film resistors with a low
temperature coefficient of resistance.
Load cells and pressure transducers are normally implemented as full
resistance bridges and do not require bridge completion resistors.
Before connecting signal wires, the Input Range Jumper should be verified for proper position.
PAXT INPUT SIGNAL WIRING
3-Wire RTD Thermocouple 2-Wire RTD
3 4 5
RT
D
TC
+
COMM.
Sense Lead
Jumper
3 4 5
RT
D
TC
+
COMM.
Sense Lead
RTD (Excitation)
3 4 5
+ -
RT
D
TC
+
COMM.
CAUTION: Sensor input common is NOT isolated
from user input common. In order to preserve the
safety of the meter application, the sensor input
common must be suitably isolated from hazardous
live earth referenced voltages; or input common
must be at protective earth ground potential. If not,
hazardous live voltage may be present at the User
Inputs and User Input Common terminals.
Appropriate considerations must then be given to the
potential of the user input common with respect to
earth common; and the common of the isolated plug-
in cards with respect to input common.
PAXS INPUT SIGNAL WIRING
Sinking Logic
Terminal 8-10:
Terminal 7:
}
In this logic, the user inputs of the
meter are internally pulled up to +5 V
with 22 K resistance. The input is active
when it is pulled low (<0 .9 V).
+
(30V max.) SUPPLY
V
USER3 USER2 USER1 USER
CO
MM
.
8 7
-
10 9
4.3 USER INPUT WIRING
Before connecting the wires, the User Input Logic Jumper should be verified for proper position. If not using User
Inputs, then skip this section. Only the appropriate User Input terminal has to be wired.
Sourcing Logic
Terminal 8-10: + VDC thru external switching device
Terminal 7: -VDC thru external switching device
In this logic, the user inputs of the meter are
internally pulled down to 0 V with 22 K
resistance. The input is active when a voltage
greater than 3.6 VDC is applied.
USER3 USER2 USER1 USER
CO
MM
.
7 8 9 10
Connect external switching device between
appropriate User Input terminal and User Comm.