Rockwell Automation 1756-IH16ISOE ControlLogix Sequence of Events Module - Manual (Page 124)

Publication 1756-UM528A-EN-P - April 2004
B-6 Integrating The HiProm GPS Module (1756HP-GPS) into a ControlLogix Sequence of Events Module System
How Does the ControlLogix
Controller Retrieve
Converted Value from the
1756HP-GPS Module? Once a ControlLogix controller receives the timestamps from an event
cascade, it may send them to the 1756HP-GPS via a message
instruction for conversion to either the following formats:
• Wall clock time (WCT) - Format that is easily understood.
Typically, the controller requests a conversion to this format for
display purposes.
• UCT - This format is a 64-bit value in microseconds, similar to
CST except that UCT starts from 1 January 1972. It is most useful
to sort data using this field prior to converting to WCT for
display purposes.
To convert CST-format timestamps to WCT, you must:
1. Add the 1756HP-GPS module to your RSLogix 5000 project via
the Generic Module profile. For more information on how to
configure the 1756HP-GPS module in an RSLogix 5000 project,
see the 1756HP-GPS module user manual available at
http://www.hiprom.com.
2. Send a Message Instruction to the 1756HP-GPS module that uses
the configuration listed in Table B.1
Table B.1
Field: Value:
Message Type CIP Generic
Service Type Custom
Service Code 32 (hex)
Class 70 (hex)
Instance 1
Attribute 1 (hex)
Source Element Controller tag where the CST-format timestamp is located
Source Length 8
Destination Destination tag for reply data