A&D AS2503, Instruction Manual

Page: 38 / 90

３－８
3.4 Wire Length Adjustment Function
If the length of the cable connecting between the bridge and amplifier is long, the bridge resistance
is lower due to the conductor resistance of the cable. For the rate of the bridge voltage drop, refer to
table 3-3 below. Before this function is employed, testing personnel made remote sensing through a
6-core cable or adjustment through values for the cable length or wire diameter.
The AS series employs a unique automatic adjustment circuit in lieu of the conventional techniques
above, thereby enabling supplying the bridge power that reflects conductor resistance. Since
high-accuracy strain measurement is possible, testing personnel can reduce measurement time and
measurement steps.
On/off for wire length adjustment can be switched using the dip switch on the bottom face of the
amplifier. See page 3-10 for more details.
Table 3-4 Rate of Voltage Drop (%) (0.5 mm
2
wire at 20

C)
Figure 3-5 Explanatory Diagram of Wire Length Adjustment Function
Distance between amplifier and bridge box (m)
B ridge Resist anc e
２０ｍ ５０ｍ １００ｍ ２００ｍ
１２０
Ω
－１．２ －３．０ －５．８ －１１．０
３５０ Ω －０．４ －１．１ －２．１ －４．１
５００
Ω
－０．３ －０．７ －１．５ －２．９
１０００
Ω
－０．１ －０．４ －０．７ －１．５
1) Automatically calculating voltage drop of the bridge voltage due to cable conductor resistance.
2) Applying the bridge voltage reflecting the voltage drop
ケーブルの導体抵抗によるブリッジ電圧の電圧降下を自動算出。
－ α
Bridge voltage -

is applied.
Amplifier
－
α
Bridge
Conventional
Amplifier
AS Amplifier
Bridge voltage
is applied.
－
α
Bridge voltage +

is applied.
Real bridge voltage
is applied.
Length: 300m, Core wire: 0.5 mm
2
, using our optional extension cable