Rockwell Automation 1746-QV,D17466.18 OPEN-LOOP VELOCITY CONTL - Manual (Page 18)

4–2 Setting Up the Hardware
Publication 1746-6.18 April 1998
Module outputs connect to a separate 2-conductor output terminal
block located beneath the input terminal block.
1746-QV Output
Terminal Block
Analog Output
(
"10v dc)
Diff.
Input
Outputs
to valves
Servo Amplifier
(Proportional)
(+)
(–)
To solenoid A
To solenoid B
A
B
+24V dc PS
0V dc PS
2
1
0V
Important: Ground the shield of the amplifier
output cable to a 0V connection in the amplifier.
Do not connect the shield to earth ground.
Note: Follow manufacturer recommendations for shielding the output
cables of the proportional amplifier. Typically, pulse-width modulated
outputs radiate electrical noise originating from the +24V dc power
supply, so isolate the shields of the amplifier output cable to a 0V dc
connection inside the proportional amplifier.
You have a choice of three configurations to match your hydraulics:
•
proportional amplifier with ramp and proportional valve
•
servo amplifier with ramp and variable-volume pump
•
Allen-Bradley 1305 Drive and hydraulic pump
You may use either of the following output voltage ranges:
•
0-10V dc for the Allen-Bradley 1305 Drive or variable-volume pump
•
–10 to +10V dc for the proportional amplifier and proportional valve
Important: Signals in this type of control system are very susceptible
to radiated electrical noise. The module is designed to set the loss-of-
sensor bit I:e.0/8 and the LDT-error bit I:e.0/0 when it detects position
values that are lost or corrupted by electrical noise.
Connect module output terminals to output devices with correct bonding:
•
connect power supply output commons together
•
electrically isolate power supply output commons from earth ground
•
use bond wires that are equal in size to signal wires
Minimize interference from radiated electrical noise with correct
shielding and grounding:
•
connect all of the following to earth ground:
– LDT flange, frame, and machine
– I/O chassis
– protective ground
– AC ground
– cable shields at one end only, preferably with 3/8” braid wire
(for analog output,
"15V dc PS, 24V dc PS, and LDT)
– terminal 4 of the input terminal block
Connect Module Outputs
to Output Devices
Minimizing Interference
from Radiated Electrical
Noise