Spectrum Controls 140 EHC 204 00sc - Manual (Page 14)

Counter / Flow Meter Input Module
15
Low Voltage Directive
This product is tested to meet Council Directive 73/23/EEC Low Voltage, since it operates with inputs under 75
VDC and 50VAC rms. It applies the safety requirements of EN 61131-2 Programmable Controllers, Part 2 –
Equipment Requirements and Tests. For specific information required by EN 61131-2, see the appropriate
sections in this publication.
Power Requirements
The module receives power through the PLC backplane from the +5VDC power supply. The maximum current
drawn for the 8 channel module is 670mA and the 4 channel module is 470mA.
Installation Considerations
This section describes several considerations to keep in mind when installing the module in a PLC system. The
following documents contain information that might help you as you install and wire the module:
•
National Electrical Code, published by the National Fire Protection Association, Boston, MA
•
IEEE Standard 518-1977, Guide for the Installation of Electrical Equipment to Minimize Electrical
Noise Inputs to Controllers from External Sources
•
IEEE Standard 142-1982, Recommended Practices for Grounding of Industrial and Commercial Power
Systems
•
Noise Reduction Techniques in Electronic Systems, by Henry W. Ott; published by Wiley-Interscience,
New York, 1976
Preventing Electrostatic Discharge
CAUTION: Electrostatic discharge can damage integrated circuits or semiconductors if you
touch module bus connector pins. Substitution of components may impair suitability for Class 1, Division 2.
To prevent electrostatic discharge, follow these guidelines when you handle the module:
•
Touch a grounded object to discharge static potential.
•
Wear an approved wrist strap grounding device.
•
Do not touch the backplane connector or connector pins.
•
Do not touch circuit components inside the module.
•
If available, use a static-safe work station.
•
When it is not in use, keep the module in its static-shield box.