Pickering 41-670 - Page 15

SECTION 2 - TECHNICAL DESCRIPTION
Page 2.3
PXI/PXIe LVDT/RVDT/Resolver Simulator Module 41/43-670
pickering
Mode 2 - 4-Wire (Fully Independent Control)
Each bank of the 41/43-670 module can be congured to simulate 4-wire operation of an LVDT as shown in the
left hand diagram below. Additionally, the A and B channels of one bank of the 41/43-670 module can be used as
separately controlled 4-wire simulation outputs with a common excitation signal as shown in the right hand diagram:
Output
Voltage
Core Displacement
-100% +100%
V
0
0
Output A
Phase Invert
Output
Voltage
Core Displacement
-100% +100%
V
0
0
Output B
Phase Invert
Figure 2.4 - 4-Wire Operation of an LVDT
Figure 2.5 - Voltage Output for Core Displacement for 4-Wire LVDTs
In this mode the two outputs of the bank are controlled fully independently allowing simulation of two separate
4-wire LVDTs on each bank, the output will be the equivalent of combining both outputs of the 5/6 wire mode with
the computation carried out internally.
VOutA = VA – VB VOutB = VA – VB
The 41/43-670’s 4-Wire Mode 2 gives better accuracy than combining two outputs of the 5/6-Wire Mode 1, also as
two independent LVDTs can be simulated per bank better density is achieved.
The output at 0% will be zero (null position), in the positive direction the output will have an inverted phase.
To congure the LVDT simulation banks to the desired modes please refer to the Programming Guide in Section 5.
VOUT=VA-VB
LVDT 4-Wire Operation - Differential Output
in
out A
out B
Excitation
Primary
Secondary
Secondary
Core
Displacement
LVDT
VOUT2
41-670 Module 4-Wire Operation - Independent Outputs
(Two Independent Channels - Common Excitation)
VOUT1
in
out A
out B
Excitation
Primary
Secondary
Secondary
Primary
Core
Core
Displacement
Displacement