User Manual
8
1080 N. Crooks Road • Clawson, MI 48017 • 800.635.0289 • Phone 248.435.0700 • Fax 248.435.8120 • www.ametekapt.com
AUTOMATION & PROCESS TECHNOLOGIES 
® 
Once the LDT has been installed, wiring connections 
can be made. The VMAX has four different connector 
options. Please refer to the part number label to help 
identify which wiring diagram is correct. There are two 
groups of connections that will need to be made. They 
are as follows:
• Power Supply Connections  
(including grounding and shielding)
• LDT Input/Output Connections
Power Supply/Ground Connections
The 953A VMAX is available with many different con-
nector/wiring options. Refer to part numbering on unit 
in question for proper wiring. See Appendex B for part 
numbering grid and qures 3.3 - 3.9 for wiring details.
Connector option S is an industry standard 5 pin 
12mm Euro style cordset with a shield. Option B is an 
8 pin DIN with a shield, and option M is a 6 pin DIN 
with a shield. To reduce electrical noise, the shield 
must be properly used. Connect the cable’s shield to 
the controller system GND. The cable shield is NOT 
connected at the transducer rod. Always observe 
proper grounding techniques such as single point 
grounding and isolating high voltage (i.e. 120/240 
VAC) from low voltage (7-30 VDC cables). 
WARNING: Do not use molded cordsets 
with LEDs!
It is preferable that the cable between the LDT and 
the interface device be one continuous run. If you are 
using a junction box, it is highly recommended that the 
splice junction box be free of AC and/or DC transient-
producing lines. The shield should be carried through 
the splice and terminated at the interface device end.
NOTE: When grounding the LDT, a single earth 
ground should be connected to the Power Supply 
Common (circuit ground). The LDT Power Supply 
Common should be connected to the Power Supply 
Common (-) terminal. The LDT power supply (+VDC) 
should be connected to the power supply positive 
Chapter 3: Wiring 
terminal (+). The LDT cable shield should be tied to 
earth ground at the power supply. The LDT analog 
common should not be connected to earth ground and 
should be used for connection to interface devices 
only. For assistance, refer to your LDT’s wiring drawing 
in this chapter.
In order for the VMAX to operate properly, the external 
power supply must provide a voltage between 7-30 
VDC. The power supply must be rated at one watt 
minimum. The power supply should provide less than 
1% ripple with 10% regulation. 
The power supply should be dedicated to the 
VMAX to prevent noise and external loads from 
affecting it. When powering up more than one 
VMAX on a single power supply, each unit will draw 
approximately one watt.
3.1: V0/V1 (Voltage)
The LDT generates a voltage output based on position. 
The 953 VMAX offers 16 Bits of resolution, and is 
fully programmable over the entire active stroke 
length. Keep in mind that there is a 2” Null Zone at the 
connector end of the LDT and a 2.5” Dead Band at the 
other end of the LDT that the magnet must stay out 
of at all times. The units come fully programmed from 
the factory and do not require re-programming unless 
desired. 
The analog output is referenced to the analog common 
terminal and should not be referenced to any of the 
other common terminals. For wiring, see Figure 3-2. 
For programming Zero and Span, See Section 3.3.
3.2: C4/C2 (Current)
The LDT generates a current output based on position. 
The 953 VMAX offers 16 Bits of resolution, and is fully 
programmable over the entire active stroke length of 
the LDT. Keep in mind that there is a 2” Null Zone at 
the connector end of the LDT and a 2.5” Dead Band at 
the other end of the LDT that the magnet must stay out 
of at all times. The units come fully programmed from 
the factory and do not require re-programming unless 
desired.
Figure 3-1: Power Supply Wiring 
Pin 1 (brown) Pin 3 (blue)
Single ended 
power supply
7-30 VDC
+ COM 
WARNING: Do not 
route the VMAX 
cable near high 
voltage sources.
!
!
Diagnostic LED
LED Color Description
None No power to LDT
Green Magnet signal detected and within programmed 
range.
Yellow Magnet signal detected, but magnet is outside of 
programmed range. 
NOTE: Magnet can be programmed in this range 
if desired.
Red No magnet signal detected. Make sure magnet 
is on the rod and within the active area. Move 
magnet back into the range and cycle power.










