Current Loop Transmitter Configurations · 2020. 12. 3. · Transmitter R In V In I RET I IN I OUT...
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Current Loop Transmitter Configurations TI Precision Labs – Current Loop Transmitters Presented by Katlynne Jones Prepared by Katlynne Jones 1
Current Loop Transmitter Configurations · 2020. 12. 3. · Transmitter R In V In I RET I IN I OUT V + + _ + _ + _ Receiver Power supply Supply & Signal Current V LOOP Sensor + Input
– 2-wire tends to be lower cost. 3-wire requires a third cable
and if
locally powered, requires an additional supply.
• Design
– More considerations in designing a 2-wire transmitter when
supplying
the driving circuitry from the transmitter.
• 4mA current budget
• Must not connect IRET to VLOOP ground
– Cannot connect multiple 2-wire transmitters to sensors or DACs
with
multiple outputs.
Show slide where
you can add the
isolation to
connect multiple
2-wire
transmitters in two
wire video
12
+ _
Power
supply
VLOOP
+ _
Receiver
+ _
Receiver
2- wire
Transmitter
(XTR116)
RIn
VIn
IRET
IIN
IOUT
V++
_
Sensor + Input
Circuitry
VOUT
GND
2- wire
Transmitter
(XTR116)
RIn
VIn
IRET
IIN
IOUT
V++
_
Sensor + Input
Circuitry
VOUT
GND
2- wire
Transmitter
(XTR116)
RIn
VIn
IRET
IIN
IOUT
V++
_
Sensor + Input
Circuitry
VOUT
GND + _
Receiver...
...V+ VREG
V+ VREG
V+ VREG
Tradeoffs cont.
13
+ _
Receiver
+ _
Receiver
+ _
Power
supply
VLOOP
2- wire
Transmitter
(XTR116)
RIn
IRET
IIN
IOUT
V+
2- wire
Transmitter
(XTR116)
RIn
IRET
IIN
IOUT
V+
2- wire
Transmitter
(XTR116)
RIn
IRET
IIN
IOUT
V+
+ _
Receiver...
...
DAC
VOUT_1
VOUT_2
VOUT_N
...
VREF V+
GND
VREFVREG
250Ω
250Ω
250Ω
Tradeoffs cont.
14
4mA
10mA
20mA
1.1V
2.75V
5.5V
+
_
Receiver
+ _
Power
supply
3- wire
Transmitter
(XTR111)
VIN
GND
IOUT
...
DAC
VOUT_1
VOUT_2
VOUT_N
...
VREF V+
GND
REF
V+
+
_
Receiver
3- wire
Transmitter
(XTR111)
VIN
GND
IOUT
V+
+
_
Receiver
3- wire
Transmitter
(XTR111)
VIN
GND
IOUT
V+
VREG
...
Tradeoffs cont.
15
16
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