HBK CB1010, Operating Manual

Page: 20 / 104

CANHEAD
CONFIGURATION
18
R
s
= value of the shunt resistor
Given: R
e
, R
s
Wanted: v
R' = (R
e
* R
s
) / (R
e
+ R
s
) Example: R
e
= 350
Ω,
R
s
= 87325
Ω
v = -0.5 * (R
e
- R') / (R
e
+ R') v = -0.001 V/V = 1.000 mV/V
Given: R
e
, v Wanted: Rs
R' = R
e
* ( ( 0.5 + v ) / ( 0.5 - v) ) Example: R
s
= 350
Ω,
v = 1.000 mV/V
Rs = 1 / ( 1/R' - 1/R
e
) R
s
= 87325
Ω
= 87.325 k
Ω
Measurement errors caused by the effect of the cable resistor in the unregulated
three‐wire circuit (CB1014) can be corrected by proper use of the shunt calibration.
Loss of sensitivity = R
e
/ (R
e
+ R
cab
) Correction by the shunt
calibration in conjunction with
the CANHEAD correction
function (see Chapter 9.1).
Offset error = 1/2 (R
cab
/ R
e
) Correction by the CANHEAD
zeroing function
Notice
To enable the CANHEAD correction function to determine the proper correction factor, the
value of the actual shunt resistor being used must be entered in the CANHEAD (the value
of the internal shunt resistor is entered at the factory). See Chapter 9.1, ”Configuration with
the MGCplus Assistant”