Emerson ControlWave GFC IStran Instruction Manual page 17

Caution
Issued Nov-09
ControlWave GFC IS Communication Interface Manual (CI-CW-GFC-ISTRAN)
When hazardous interface signal input HRX3 is at a high (positive)
level, NPOUT turns on and can supply power to an external device.
When HRX3 is at a low (or negative) level, NPOUT turns off. You
determine the voltage drop between NPIN and NPOUT by multiplying
the NPOUT load current by the NPIN to NPOUT on-resistance. You
must also take into account the resistance of the associated field wiring
when you calculate the total drop between the power supply and the
load.
In order to minimize resistance between NPIN and NPOUT, the IStran
does not provide over-current. You must install a fuse or other means of
over-current protection at the power source to prevent damage to the
IStran, power source, or load in case of a short circuit or other over-
current condition.
Function and Electrical Characteristics 2-7