Chapter 3: 955QD Overview
Installation, Programming and Maintenance Manual
6
3.3: Quadrature Output Resolution and Speed
The internal resolution of the 955QD Gemco LDT is 0.001”. This would be represented to the encoder input
device by specifying an output resolution of 1,000 cycles per inch for the transducer. Although the typical
resolution is 1,000 cycles per inch (CPI), the transducer can be ordered with virtually any CPI setting.
For a typical rotary type shaft encoder with incremental quadrature output, the output frequency of the
pulses is governed by the resolution of the encoder (pulses per turn) and the rotational speed (RPM) of the
encoder. The output pulses rate from the LDT transducer is xed and is controlled internally and can be
specied by the customer. The output frequency must be specied so that it does not exceed the maximum
pulse rate of the encoder input card the sensor is connected to. The output pulse frequency range can be
ordered from 10KHz to 1MHz.
3.4: 955QD Wiring Connections
Once the LDT has been installed, wiring connections can be made. There are two groups of connections you
will need to make. They are as follows:
• Power Supply Connections (including grounding and shielding)
• LDT Input/Output Connections
Power Supply/Ground Connections
The 955QD Brik standard cable is Alpha 6334, a multi-conductor cable. 10 conductors of 24ga, with an
aluminum/polyester/aluminum foil with drain wire plus an overall braid of tinned copper shield. Cable O.D.
is .270. 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 end. Always observe proper
grounding techniques such as single point grounding and isolating high voltage (i.e. 120/240 VAC) from low
voltage (10 - 30 VDC cables). Whenever possible, this cable should be run in conduit by itself.
UNIPOLAR
Figure 3-1:
Power Supply Wiring
WARNING:
Do not route the Brik with Quadrature Output cable near high voltage sources.
Single ended
powe supply
+10 to +30 VDC
+ COM
Pin 2 (red)
Pin 1 (black)
