Omega Vehicle Security OM5-C manual OM5-TX, Wire Transmitter Interface Modules

OM5-TX

2-Wire Transmitter Interface Modules

FEATURES

●ISOLATED +20VDC 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 standard +1 to +5V or +2 to +10V output signal (Figure 1). An isolated +20VDC regulated power supply is provided to power the current transmit-

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 nominal +20VDC 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 20Ω 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.

2-Wire
Transmitter
+EXC	4		LPF	Isochopper™
	4					LPF	20
				Amplifier				VOUT
+In		Surge
	6			Pat Pending
	3	Suppression
		and					19
	5
		Protection						I/O Common
–In
	2
	3				+V	–V	22
				Isolated				RD EN\
–EXC	1
				Excitation
					Isolated
	20Ω			Source
					Computer-Side
	0.1% plug-in
					Power
	OMX-1362-C
Backpanel
Term Block
	1
	NC
	2
	NC						17
		+V						+5V
			Isolated
						Power
		–V	Field-Side
						Oscillator
			Power				16	Power
								Common

FIGURE 1. OM5-TX Block Diagram.

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