Omega Vehicle Security OM5-C manual OM5-IFI, Frequency Input Modules

OM5-IFI

Frequency Input Modules

FEATURES

●ACCEPTS FREQUENCY INPUTS OF 0 to 100kHz

●PROVIDES HIGH LEVEL VOLTAGE OUTPUTS

●TTL LEVEL INPUTS

●1500 VOLT TRANSFORMER ISOLATION

●ANSI/IEEE C37.90.1-1989 TRANSIENT PROTECTION

●INPUT PROTECTED TO 240VAC CONTINUOUS

●±0.05% ACCURACY

●MIX AND MATCH OM5 TYPES ON BACKPANEL

●CSA CERTIFIED, FM APPROVED, CE COMPLIANT

DESCRIPTION

Each OM5-IFI Frequency input module provides a single channel of fre- quency input which is isolated and converted to a high level analog voltage output. This voltage output is logic switch controlled, which allows these modules to share a common analog bus without the requirement of external multiplexers (Figure 1).

The frequency input signal can be a TTL level signal or a zero-crossing signal. Terminal 3 (+In) on the field-side terminal block is the “common” or ground connection for input signals. A TTL signal is connected from terminal 2 (–In) to terminal 3 (+In), while a zero-crossing signal is connected from terminal 4 (+EXC) to terminal 3 (+In). Input circuitry for each of the signal types has hysteresis built in. An input signal must cross entirely through the hysteresis region in order to trigger the threshold comparator.

A 5.1V excitation is available for use with magnetic pick-up or contact- closure type sensors. The excitation is available on pin 1 (–EXC) and the excitation common is pin 3 (+In).

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 special circuit in the input stage of the module provides protection against accidental connection of power-line voltages up to 240VAC.

Zero-Crossing					Threshold		F to V
			4		Comparator
Inputs	+EXC
+		4			Signal		LPF	20	VOUT
				Surge	Isolation
–	+In		6
–	TTL	3		Suppression
				and
	Inputs							19
			5
+				Protection		+V	–V		I/O Common
	–In
		2
			3
	–EXC							22
						Isolated			RD EN\
		1
						Computer-Side
				5.1V		Power
	Backpanel
	Term Block
				1
				NC
				2
				NC				17
				+V					+5V
					Isolated
							Power
				–V	Field-Side
							Oscillator
					Power			16
									Power Common

FIGURE 1. OM5-IFI Block Diagram.

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