Watlow CLS200 - Manual (Page 38)

Chapter 2: Installation CLS200 Series User’s Guide
22 Watlow Anafaze Doc.# 0600-3050-2000
Table 2.1 Cable Recommendations
Noise Suppression
The CLS200’s outputs are typically used to drive solid state
relays. These relays may in turn operate more inductive
types of loads such as electromechanical relays, alarm
horns and motor starters. Such devices may generate elec-
tromagnetic interference (EMI or noise). If the controller is
placed close to sources of EMI, it may not function correct-
ly. Below are some tips on how to recognize and avoid prob-
lems with EMI.
For earth ground wire, use a large gauge and keep the
length as short as possible. Additional shielding may be
achieved by connecting a chassis ground strap from the
panel to CLS200 case.
Symptoms of RFI/EMI
If your controller displays the following symptoms, suspect
EMI:
• The controller’s display blanks out and then reenergiz-
es as if power had been turned off for a moment.
• The process variable does not display correctly.
EMI may also damage the digital output circuit—so digital
outputs will not turn on. If the digital output circuit is dam-
aged, return the controller to Watlow Anafaze for repair.
Function Mfr. P/N
No. of
Wires
AWG mm 2
Maximum
Length
Analog Inputs
Belden 9154
Belden 8451
2
2
20
22
0.5
0.5
RTD Inputs
Belden 8772
Belden 9770
3
3 20
22 0.5
0.5
Thermocouple Inputs T/C Ext. Wire
2 20 0.5
Control Outputs and
Digital I/O
Belden 9539
Belden 9542
Ribbon Cable
9
20
50
24
24
22 to 14
0.2
0.2
0.5 to 2.5
Analog Outputs
Belden 9154
Belden 8451
2
2 20
22 0.5
0.5
Computer Communica-
tion: EIA/TIA-232, 422
or 485, or 20 mA
Belden 9729
Belden 9730
Belden 9842
Belden 9843
Belden 9184
4
6
4
6
4 24
24
24
24
22 0.2
0.2
0.2
0.2
0.5 4,000 ft. (1,219 m)
4,000 ft. (1,219 m)
6,000 ft. (1,829 m)