24
OM5-TX
2-Wire Transmitter Interface Modules
ter. This allows a 2-wire loop powered transmitter to be directly connected
to the module without requiring an external power supply. The regulated
supply will provide a n20VDC at a loop current of 4mA to 20mA.
The OM5-TX will provide a 1500V isolation barrier for non-isolated 2-wire
field transmitters. It can also be used when additional isolation is required
between an isolated 2-wire transmitter and the input stage of the control
room computer.
The voltage output is logic switch controlled, which allows these modules
to share a common analog bus without the requirement of external
multiplexers.
The modules are designed with a completely isolated computer side circuit
which can be floated to
±
50V from Power Common, pin 16. This complete
isolation means that no connection is required between I/O Common and
Power Common for proper operation of the output switch. If desired, the
output switch can be turned on continuously by simply connecting pin 22,
the Read-Enable pin to I/O Common, pin 19.
A precision 20
Ω
current conversion resistor is supplied with the module.
Sockets are provided on the OM5-BP backpanels to allow installation of
this resistor. Extra resistors are available under part number OMX-1362-C.
All field inputs are fully protected from accidental connection of power-line
voltages up to 240VAC. The module has a 3dB bandwidth of 100Hz. Signal
filtering is accomplished with a six-pole filter, with two poles on the field
side of the isolation barrier, and the other four on the computer side.
FIGURE 1. OM5-TX Block Diagram.
FEATURES
●
IS20VDC CURRENT LOOP SUPPLY
●
PROVIDES ISOLATION FOR NON-ISOLATED 2-WIRE
TRANSMITTERS
●
HIGH LEVEL VOLTAGE OUTPUT: +1V to +5V or +2V to +10V
●
1500Vrms TRANSFORMER ISOLATION
●
ANSI/IEEE C37.90.1-1989 TRANSIENT PROTECTION
●
INPUT PROTECTED TO 240VAC CONTINUOUS
●
100dB CMR
●
100Hz SIGNAL BANDWIDTH
●
±
0.05% ACCURACY
●
±
0.02% LINEARITY
●
CSA CERTIFIED, FM APPROVED, CE COMPLIANT
●
MIX AND MATCH OM5 TYPES ON BACKPANEL
DESCRIPTION
Each OM5-TX 2-wire transmitter interface module provides a single chan-
nel which accepts a 4 to 20 mA process current input and provides a
st1 to +5V or +2 to +10V output signal (Figure 1). An isolated
+20VDC regulated power supply is provided to power the current transmit-
LPF
+In
–In
–EXC
Backpanel
Term Block
1
2
NC
4
6
5
3
Surge
Suppression
and
Protection
Isolated
Field-Side
Power
Isochopper™
Amplifier
Pat Pending
4
3
2
1
+EXC
–V
+V
–V
+V
Isolated
Computer-Side
Power
NC
LPF
V
OUT
20
19
22
I/O Common
RD EN\
Power
Oscillator
+5V
17
16
Power
Common
2-Wire
Transmitter
20
Ω
0.1% plug-in
OMX-1362-C
Isolated
Excitation
Source
Содержание OM5-C
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