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L V D Ts. What is an LVDT? An LVDT is a Linear Position Sensor With a Proportional Analog Output An LVDT has 2 Elements, a Moving Core and a Stationary Coil Assembly. L V D Ts. What Do the Letters LVDT Stand For?. . L V D Ts. Linear Variable Differential TransformerTransformer:
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1. Everything You Always Wanted To Know About LVDTs But Were Afraid To Ask - - - or - - -
“What The Hell Is An LVDT, Anyway?”
2. L V D Ts What is an LVDT?
An LVDT is a Linear Position Sensor
With a Proportional Analog Output
An LVDT has 2 Elements, a Moving
Core and a Stationary Coil Assembly
3. L V D Ts What Do the Letters LVDT Stand For?
4. L V D Ts Linear Variable Differential Transformer
Transformer: AC Input / AC Output
Differential: Natural Null Point in Middle
Variable: Movable Core, Fixed Coil
Linear: Measures Linear Position
5. FYI: Macro Sensors LVDTs Macro Sensors LVDTs have range specified as ± from null position
Nominal range is part of Model No.
Total range is 2x nominal range
6. Macro Sensors LVDT Model Numbering Initial Letters : LVDT Series Designation
Numbers Following Letters: Diameter or Body Size in Thousandths of an Inch
Following Dash: Nominal Range from Null in Thousandths of an Inch
Standard Option: Dash, then 3 Digits
Special Unit: Dash Followed by 4 Digits
7. Macro Sensors LVDT Model Numbering Example: PR 750-1000- 010 LVDT
PR = PR Series General Purpose LVDT
750 = 0.75 inch (3/4 Inch) Diameter
-1000 = Nominal Range of ±1.00 Inch;
Total Range of 2.00 Inches
- 010 = Optional Teflon Bore Liner
8. L V D Ts
36. How to Select an LVDT First Choice to Make:
Free Core vs. Guided Core
Free Core
Frictionless Operation Possible
Mechanically Coupled Core
Guided Core
Bearings with Friction, Stiction, etc.
Spring- or Air-Loaded Core
37. Free Core LVDTs
Generally Less Expensive
Many Ranges and Sizes to Choose
More Complicated to Install
38. Guided Core LVDTs Usually Simpler to Install
Perceived as More Expensive
More Limited Selection of Ranges and Limited to Short Strokes
39. How to Select an LVDT Second Choice to Make:
AC in / AC out vs. DC in / DC out
AC operation: External Support Electronics
DC operation: Built-in Support Electronics
40. AC in / AC out ADVANTAGES
Flexible in Applications- Span and Zero Adjustable, etc.
Many Ranges and Sizes to Choose
More Robust to Environments
LIMITATIONS
Requires External Support Electronics
Requires Extra Connections to LVDT
Potential Electrical Noise Susceptibility
Potential Problems with Long Cables
41. DC in / DC out ADVANTAGES
Simpler to Hook Up
Precalibrated Operation
Several Input/Output Choices
LIMITATIONS
Temperature Environment
No Span or Zero Adjustability
Size Constrained by Internal Electronics
42. Free Core AC LVDT Series PR General Purpose, Many Ranges
PRH G. P. Legacy Replacement
CD Miniature Size, Shorter Ranges
HSA Hermetically Sealed, Blind Bore
HSAR Hermetically Sealed, Thru Bore
SQ Heavy Duty Industrial Housing
HLR UL Listed Class I, Div. 2 HazLoc
HSE Hermetically Sealed, Blind Bore
HSER Hermetically Sealed, Thru Bore
43. Free Core DC LVDT Series DC General Purpose, Voltage Out
HSD Hermetically Sealed, Blind Bore
HSDR Hermetically Sealed, Thru Bore
HSDI 4-20 mA Loop Powered (2-Wire)
PRDC Legacy 24 Volt, Ratiometric I/O
PTI 4-20 mA Loop Powered (2-Wire)
FM Approved Intrinsically Safe (I.S.)
Class I, Div. 2 Hazloc with Barriers
44. Free Core DC LVDT Series HSE Hermetically Sealed, Blind Bore*
HSER Hermetically Sealed, Thru Bore*
HSDI 4-20 mA Loop Powered (2-Wire)
PRDC Legacy 24 Volt, Ratiometric I/O
PTI 4-20 mA Loop Powered (2-Wire)
FM Approved Intrinsically Safe (I.S.)
Class I, Div. 2 Hazloc with Barriers
* Available fall 2005
45. Guided Core LVDTs Sleeve Bushing or Linear Ball Bearing
Spring Extended (push LVDTs)
Spring Retracted (tension LVDTs)
Air Extended, Spring Retracted
46. Guided Core LVDT Series GSA Lowest Cost, AC only
GHS Good Precision, AC and DC
GHSR Good Precision, AC and DC
BBP/T Highest Precision, AC only
GHSR-A Air-Extended GHSR Series
GHX Air-Extend, Long Retraction
BBP/T-A Air-Extended BB Series
47. LVDT Support Electronics *** For AC LVDTs only ***
DCM-1000 DC Powered OEM Electronics*
LPC-2100 AC Line Powered*
LVC-2412 24 Volt DC Powered*
DMC-A2-Series Dual Channel Controller
DMI-A1 Series Single Channel Controller
* Discontinued as of mid 2006
48. LVDT Support Electronics DCM-1000
Unpackaged PC Board for OEMs
Roughly Same Cost as DC LVDT
Voltage Output Only, w/ Span + Zero
+/- 15 V DC Input Power
49. LVDT Support Electronics LPC-2100
DIN-rail Mounting
Voltage or 3-Wire Current Output
AC Power Line Operation
Span and Zero Adjustments
50. LVDT Support Electronics LVC-2412
DIN-rail Mounting
Voltage or 3-Wire Current Output
12 - 24 V DC Operation
Span and Zero Adjustments
51. LVDT Support Electronics DMI Series Single Channel Indicator
AC Power Line or 24 VDC Operation
5-1/2 Digit LED Display
Adjustable Set Points
2 or 4 5-Amp Relay Option
RS 232 / Ethernet Output Options
Software
Scaleable Analog Outputs
52. LVDT Support Electronics DMC Series Dual Channel Controller
AC Power Line or 24 VDC Operation
6-1/2 Digit LED Display
Scrolling setup screens
Adjustable Set Points
4 5-Amp Relays
RS 232 (Std) / (Ethernet Optional)
Software
Scaleable Analog Outputs
53. Macro Sensors
Over 400 Years of Collective Experience
In The LVDT Business
54. FACILITIES 20,000 Sq. Ft. Facility in Pennsauken, NJ
ISO 9001 Certified Company
Certificated November 8th 2000.
56. CERTIFICATIONS Underwriters Laboratories
- HLR Series AC-LVDTs
Factory Mutual
Factory Mutual Intrinsic Safety Certification for PTI 750 Series Loop-Powered Position Transmitters
CE
DC 750 Series DC LVDTs
DCSE Series DC LVDTs
HSD, HSDR Hermetically Sealed LVDTs
GHSD, GHSDR Spring Loaded DC-LVDTs