Ground and shield your i/o devices – Rockwell Automation 1771-QDC, D17716.5.93(Passport) PLASTIC MOLDING MODULE User Manual

Page 41

Install the QDC Module

Chapter 2

2-9

ATTENTION: The QDC module has ESD protection to 20kV,
but you can damage the module by accidental application of the
wrong voltage to the I/O terminals. Do not exceed:

This voltage:

On these terminals:

When in:

+12V dc

input (18 thru 10)

any mode

+12V dc

output (09 thru 02)

voltage mode

+24V dc

output (09 thru 02)

current mode

Analog inputs and outputs are sensitive to electrical noise interference.
Take care to ground and shield them properly.

Guidelines:

Use 22-gage (or larger) twisted-pair cable, 100% shielded with drain

wire, such as Belden 8761. For cable distances over 50 ft, use 18-gage
cable such as Belden 8760.

Ground the cable shield at one end only; generally at the sensor or

amplifier end, not at the I/O chassis (see Figure 2.4 and Figure 2.5).

Figure 2.4

Shielding Differential Inputs

Connect the cable shield

and case ground to earth

ground at the Input Sensor

Input Sensor

QDC Module Input

Input Module Common

(should float)

–

10910ĆI

Ground and Shield

Your I/O Devices