Rockwell Automation 1794-VHSC Very High Speed Counter Module Installation Instruction User Manual
Cat. no. 1794-vhsc, Install your very high speed counter module
 
Publication 1794-IN067C-EN-P - January 2012
Installation Instructions
FLEX I/O™ Very High Speed Counter
Cat. No. 1794-VHSC
Install Your Very High Speed Counter Module
The module mounts on a 1794-TB3G or 1794-TB3GS terminal base.
1. Rotate the keyswitch (3) on the terminal base (4) clockwise to position 1 as
required for this type of module.
IMPORTANT
This module must be used with 1794-ACN15 or 1794-ACNR15 
Series B or later ControlNet adapters in ControlNet systems.
Important User Information
Solid state equipment has operational characteristics differing from those of 
electromechanical equipment. Safety Guidelines for the Application, Installation and 
available from your local
Rockwell Automation sales office or online at
) describes some important differences
between solid state equipment and hard-wired electromechanical devices. Because of 
this difference, and also because of the wide variety of uses for solid state equipment, 
all persons responsible for applying this equipment must satisfy themselves that each 
intended application of this equipment is acceptable.
In no event will Rockwell Automation, Inc. be responsible or liable for indirect or 
consequential damages resulting from the use or application of this equipment.
The examples and diagrams in this manual are included solely for illustrative purposes. 
Because of the many variables and requirements associated with any particular 
installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual 
use based on the examples and diagrams.
No patent liability is assumed by Rockwell Automation, Inc. with respect to use of 
information, circuits, equipment, or software described in this manual.
Reproduction of the contents of this manual, in whole or in part, without written 
permission of Rockwell Automation, Inc. is prohibited.
Throughout this manual we use notes to make you aware of safety considerations.
WARNING
Identifies information about practices or circumstances that can 
cause an explosion in a hazardous environment, which may lead to 
personal injury or death, property damage, or economic loss.
IMPORTANT
Identifies information that is critical for successful application and 
understanding of the product.
ATTENTION
Identifies information about practices or circumstances that can lead 
to personal injury or death, property damage, or economic loss. 
Attentions help you identify a hazard, avoid a hazard, or recognize the 
consequence
ATTENTION
Environment and Enclosure
This equipment is intended for use in a Pollution Degree 2 industrial 
environment, in overvoltage Category II applications (as defined in IEC 
60664-1), at altitudes up to 2000 m (6562 ft) without derating.
This equipment is considered Group 1, Class A industrial equipment 
according to IEC/CISPR 11. Without appropriate precautions, there may be 
difficulties with electromagnetic compatibility in residential and other 
environments due to conducted and radiated disturbances.
This equipment is supplied as open-type equipment. It must be mounted 
within an enclosure that is suitably designed for those specific 
environmental conditions that will be present and appropriately designed 
to prevent personal injury resulting from accessibility to live parts. The 
enclosure must have suitable flame-retardant properties to prevent or 
minimize the spread of flame, complying with a flame spread rating of 
5VA, V2, V1, V0 (or equivalent) if non-metallic. The interior of the 
enclosure must be accessible only by the use of a tool. Subsequent 
sections of this publication may contain additional information regarding 
specific enclosure type ratings that are required to comply with certain 
product safety certifications.
In addition to this publication, see:
• Industrial Automation Wiring and Grounding Guidelines, publication
, for additional installation requirements
• NEMA Standard 250 and IEC 60529, as applicable, for explanations
of the degrees of protection provided by enclosures
ATTENTION
FLEX I/O is grounded through the DIN rail to chassis ground. Use zinc 
plated yellow-chromate steel DIN rail to assure proper grounding. The use 
of other DIN rail materials (for example, aluminum or plastic) that can 
corrode, oxidize, or are poor conductors, can result in improper or 
intermittent grounding. Secure DIN rail to mounting surface approximately 
every 200 mm (7.8 in.) and use end-anchors appropriately.
ATTENTION
Prevent Electrostatic Discharge
This equipment is sensitive to electrostatic discharge, which can cause 
internal damage and affect normal operation. Follow these guidelines 
when you handle this equipment:
• Touch a grounded object to discharge potential static.
• Wear an approved grounding wriststrap.
• Do not touch connectors or pins on component boards.
• Do not touch circuit components inside the equipment.
• Use a static-safe workstation, if available.
• Store the equipment in appropriate static-safe packaging when not 
in use.
ATTENTION
If multiple power sources are used, do not exceed the specified isolation 
voltage.
ATTENTION
Do not remove or replace a Terminal Base unit while power is applied. 
Interruption of the backplane can result in unintentional operation or 
machine motion.
ATTENTION
During mounting of all devices, be sure that all debris (metal chips, wire 
strands, and so on) is kept from falling into the module. Debris that falls 
into the module could cause damage on power up.
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