Printronix PrintNet Enterprise - Manual (Page 276)

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Chapter 6 Technical Information
Technical Information
Opto-couplers
The opto-couplers are Vishay SFH6916 or equivalent with the following basic
specifications:
NOTE: Please check the Vishay SFH6916 datasheet for electrical
specifications.
GaAs Light Emitting Diode
Reverse Voltage (Vr) : 6 V
Forward Current (DC) : 50 mA
Peak Forward Current (Ifp) : 2.5 A
NPN Silicon Photo Transistor
Isolation Voltage (Vr) : 3750 V r.m.s.
Collector to Emitter voltage (Vceo) : 70 V
Collector current : 50 mA
High switching speed
UL approved
The inputs of the GPIO board (the LEDs of 8 opto-couplers) are protected
against overcurrent by the inclusion of a 4700 Ohm resistor in the anode
connection. This allows for an input voltage range between 5 and 24 VDC.
The opto-coupler outputs are open collector transistors. By design the output
current available is set at 3 ma. max. This value is based upon an opto-
coupler current transfer ratio of 100% at an ambient temperature of 50
degrees C. Load currents greater than 3 ma. will cause the transistor to come
out of the saturation, resulting in a rise in the output voltage and possible
damage to the transistor. For safety purposes a voltage no greater than 42
volts DC should be applied to the GPIO board. The GPIO board has a
provision for mounting resistors, either in the connection between the actual
output pin and the collector of the output transistor or from a common
connector pin (17) to the collector of the output resistor. See the drawing on
page 280.
Relays
Relays are the NAiS TX type and are 2-Amp high capacity relays with the
following basic specifications:
NOTE: Please check the NAiS TX type relay datasheet for complete
electrical specifications.
Surge withstand between coil and contacts : 2500 V
Breakdown voltage between coil and contact : 2000 V
Nominal switching capacity : 2 A @ 30 V
Maximum switching voltage : 220 V DC
Maximum switching current : 2 A
Contact settling time : 4 mS (max)
The relays are type DPDT of which a single SPDT contact is made available
on the I/O connector.