Hardware
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2.3 Power Requirements
Supply voltage requirements for NTXS series models is as follows:
NT2S-SF121B-EV2 +24VDC + 10%, 1.5W maximum on Power Port 
NT2S-SF122B-EV2 +5VDC + 10% on PLC port 
NT2S-SF123B-EV2 +5VDC + 10% on PLC port
NT2S-SF125B-E +24VDC + 10%, 1.5W maximum on Power Port 
NT2S-SF126B-E +5VDC + 10% on PLC port 
NT2S-SF127B-E +5VDC + 10% on PLC port
NT3S-ST121B-E +24VDC + 10%, 3.5W maximum on Power Port 
NT3S-ST123B-E +24VDC + 10%, 3.5W maximum on Power Port 
NT3S-ST124B-E +24VDC + 10%, 3.5W maximum on Power Port 
NT3S-ST126B-E +24VDC + 10%, 3.5W maximum on Power Port
Please follow the instructions given below while making power supply connections for models:
1. Follow the wiring diagram on the sticker of the unit which shows terminals.
2. To make a connection strip about 7mm of insulation of the wire, turn the connector screw 
counter-clock wise until the gap is wide open. Insert the wire all the way in and turn the screw 
clockwise until it is tight.
3. Wire lengths should be minimum. Wires should run in pairs with a neutral or common paired 
with a live or signal wire.
4. NTXS +24VDC model is fused internally with a self resetting 60V , 400mA fuse. It is recom 
mended that all input power lines be protected from product failure by a fuse or breaker.
5. Adequate strain relief must be provided for the power connector, to ensure that vibration does 
not cause the power connector to be pulled out.
6. All the NTXS products are housed in a moulded ABS plastic case which eliminates any 
electrical shock hazard. Hence Safety Earth is not required to be connected to the chassis of 
the unit.
7. The DC ground is not directly coupled to Earth ground internally. The unit is designed to 
operate properly whether or not the DC ground is connected to the Earth ground. We do recom 
mend, however, that if the DC ground has to be connected to the Earth ground, the Earth 
connection should be made to a central star point as poor site earths can introduce noise into a 
system.
8. Do not power unit and inductive loads with the same power supply even though there is 
enough immunity in the NTXS to withstand the transients present on these lines. A void using 
power supplies with large capacitive outputs which may cause problems if power is cycled within 
a short time period.
9. If wiring is to be exposed to lightening or surges, use appropriate surge suppression devices.
10. Keep AC, high energy and rapidly switching DC wiring sep arate from signal wires. 
1 1. Connecting high voltages or AC power mains to the DC input will make unit unusable and
may create an electrical shock hazard to personnel. Such a failure or shock could result in 
serious personal injury , loss of life and/or equipment damage. DC voltage sources should 
provide proper isolation from main AC power and similar hazards.