Rockwell Automation 1746-QS,D17466.19 SYNCHRONIZED AXES MODULE - Manual (Page 12)

2–4
Publication 1746-6.19 March 1998
Important: To minimize the adverse effects of ground loops, you must
isolate power supply and signal commons from earth ground as follows:
1. Connect power supply commons to IFM Com terminal (50), and
LDT commons to LDT Com terminals of the IFM terminal block.
Be sure that they are isolated from earth ground.
2. Connect the cable shield of the servo or proportional amplifier
output cable to a zero potential terminal inside the amplifier.
3. Use bond wires that are equal in size to signal wires.
4. When practical, use one power supply to power only your LDTs.
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 integrated with a proportional valve
•
servo amplifier and variable-volume pump or servo valve
•
Allen-Bradley 1305 Drive and hydraulic pump
You may use either of the following output voltage ranges:
•
0-10V dc for an Allen-Bradley 1305 Drive or variable-volume pump
•
–10 to +10V dc for a proportional or servo amplifier
If using servo valves, you must convert the module’s output from
voltage to current.
Output Polarity
In most hydraulic systems, the actuator extends (with increasing
LDT counts) when a positive voltage is sent to the output. The
extend direction is defined as the direction that causes the LDT to
return increasing counts moving away from the head.
You can make these selections in the Config word that affect output:
•
To generate a positive drive output (0-10V dc) regardless of move
direction, you can select Absolute Mode.
•
To extend the actuator by sending a negative voltage to the
output, you can select Reverse Drive Mode.
For additional information on the Configuration word, select that
subject in Help Topics.
Connecting Outputs
to Output Devices