19
Offset/Polarity
is not particular to a type of input or output, but the driver handles analog
and digital (binary) inputs and outputs differently. To set these values appropriately, you
should understand how the driver uses them.
Offset/Polarity
Notes
Analog Input
(BAI)
Offset
value (positive or negative) adds a fine adjustment to a sensor
reading after all scaling for calibration.
EXAMPLE
If a sensor reads 74.9°F when the actual measured value
is 73.6°F, enter an
Offset
of
–1.3
to calibrate the sensor to the
measured value.
Analog Output
(BAO)
You can use the
Offset
value (positive or negative) to calibrate an
output, but you generally do not need to. If used, the driver adds the
offset value to the wire input value before performing any scaling
calculations to determine the Room Controller's output.
Digital (Binary)
Input (BBI)
Polarity
determines the microblock's present value when no signal is
received from the equipment.
When no signal is received from the equipment, if
Polarity
is set to:
normal
—present value is
off
reversed
—present value is
on
Digital (Binary)
Output (BBO)
Polarity
determines the Room Controller's output based on the
control program's signal to the microblock.
When the control program's signal to the microblock is
on
, if
Polarity
is set to:
normal
—output is
on
reversed
—output is
off
NOTE
Regardless of
Polarity
, the output will be off if the Room
Controller loses power. You can set the relay contact for each output
on the Room Controller to be open or closed if the Room Controller
loses power.
EXAMPLE
To set up an output for on/off heat in a cold climate:
Output jumper—NC (normally closed)
Polarity—reversed
If the Room Controller loses power, the jumper causes the contact to
close and the heat turns on.
When the signal to the microblock is on, the Room Controller output
is off, the relay is closed, and the heat is on.
Offset/Polarity
values
