Rockwell Automation FactoryTalk View Machine Edition Users Guide - Manual (Page 406)

F ACTORY T ALK V IEW M ACHINE E DITION U SER ’ S G UIDE
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How the Handshake reset type works
How the Enter handshake connection resets the Enter connection depends on which
Handshake reset type you select:
Set up the data source to send a non-zero value to the Enter handshake connection when it
has read the new value at the Value connection, and then to reset the Enter handshake
connection to 0.
If the Enter key handshake time expires before the Enter handshake connection resets the
Enter connection, an error message is sent to FactoryTalk
® Diagnostics.
How handshaking works
If you use the Enter handshake connection, handshaking works like this:
1. When the operator presses the Enter button, the value is sent to the Value connection
and the “Enter key control delay” timer begins timing. (The use of a delay is optional.)
2. If you specify an Enter key control delay, when the time is up, the Enter connection is
set to 1. If you don’t use the delay, the Enter connection is set to 1 as soon as the
operator presses Enter.
As long as the Enter connection is set to 1, the operator cannot send new values to the
data source.
If the Handshake reset type is Non-zero Value, the Enter handshake connection must
be 0 when the delay expires in order to set the Enter connection to 1.
3. When the Enter connection is set to 1, the “Enter key handshake time” timer begins
timing.
4. The Enter connection remains set until the Enter key handshake time expires or until
reset by the Enter handshake connection, whichever happens first.
With this handshake reset
type
The Enter connection is set to 0 when
Non-zero Value The Enter handshake connection has a non-zero value.
If the Enter handshake connection already has a non-zero value
when the value is sent to the Value connection (or when the Enter
key control delay has expired, if the delay is used), then the Enter
connection is not set to 1, and Enter key handshaking does not take
place.
Zero to Non-zero transition The Enter handshake connection changes from 0 to a non-zero
value.