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Use with a data logger
BF5 User Manual v 2.3
The Htr+ and Htr- cables provide power to the BF5 heater. If this power
supply is separate from the data logger power, it should be a fully isolated
supply to ensure that no current flows between the data logger power
supply negative terminal and the heater power supply negative terminal.
Note
The various grounds (Htr-, DL-Gnd, Signal Gnd) are all connected at the
BF5, so if the heater is in use, then the Signal Gnd must be able to float
relative to the two power grounds at the logger end.
Use a data logger with differential sensor inputs to avoid potential
errors caused by an incorrectly wired heater earth return
.
Alternately, if you have to use a single-ended logger, the requirement is
that either the logger or the heater PSU must be able to float relative to
the other, and there must be no connection between signal and power
grounds or BF5 enclosure anywhere except inside the BF5.
Simplified output schematic
This schematic shows a simplified version of the output circuitry,
protection components and grounding details.