120
c
HAPTER
5:
Advanced Operation
Model 372 AC Resistance Bridge and Temperature Controller
Therefore, a 16
)/
10 W resistor would be an acceptable solution in this scenario.
Keep in mind that higher resistance conversion resistors can be used in combination
with lower warm-up heater current settings to minimize power loss; however, this
comes with a cost of lost resolution. For example, a 100
)
current conversion resistor
can be used with a maximum current of 100 mA to attain 10 V across the 100
)
resis-
tor. However three bits of resolution loss occur as a result of this, decreasing the reso-
lution from 0.003% of range to 0.02% of range.
To accommodate scenarios where your load resistance is small (on the order of
100
)
), the current-to-voltage conversion resistor must be adjusted to maintain 10 V
across it. For example, if the load resistor is 100
)
, an added parallel resistor must be
sized appropriately to maintain an equivalent resistance of 15.8
)
in order to main-
tain 10 V at full scale output, assuming the maximum current is still set to 0.63 A.
1/(100
)
)+1/X = 1/(15.8
)
)
1/X = 0.05329
)
X = 18.76
)
Series and parallel combinations can be used with standard resistor values to reach
the desired equivalent resistance.
Menu navigation:
Interface
Q
Emulation Mode (
None, Model 370
)
Interface command:
EMUL