Allen-Bradley 1779-KFMR User Manual page 182

Chapter 12
Token-Hold Factor — Determines the amount of time a node will hold
the token and thus be able to transmit messages. Valid entries are 1
through 256 (1 through FF hex). The token-hold factor is a multiple of
the token-hold time. The default token-hold factor is 1. For example, if
you set the token-hold factor at 6 for a node, the node will hold the token
for 6 times the default time. For information on performance
characteristics of the link, see the Data Highway II System Design Guide
(Publication 1779-6.3.1). Default is 01 hex. Data field is one byte long.
Number of ENQs — Determines the number of ENQuiries (ENQs) a
KFL will send to its host (in an effort to solicit an acknowledgment of a
message transmission) before the KFL reports a communication error to
the remote station that originated the message. The KFL will send an
enquiry when it does not receive a response to a message within a
specified time. Data field is one byte long. Valid entries are
01 to FF hex. Default is three ENQs.
Number of Attempts — Determines the number of times the KFL will
transmit a message to its host [when it receives Negative
Acknowledgments (NAKs) in response] before the KFL reports a
communication error to the remote station that originated the message.
When a KFL transmits a message to its host device, it expects an ACK
response. When a KFL receives a NAK instead of an ACK, it retransmits
the message unless it has already reached the number of attempts set in
this parameter. Data field is one byte long. Valid entries are
01 to FF hex. Default is 3.
Response Timer — Determines the amount of time the KFL waits for a
response (ACK or NAK) from its host device to a message transmission
before sending an ENQ (enquiry) to its host device. Data field is
two bytes long. Time base is 10 ms. Valid entries are
01 (10 ms) to FF FF hex (10 min. 54 sec.). Default is 1 second.
Remote-Reply Timer — Determines the amount of time a KFL or KFM
will wait for a supervisory reply message from a remote station before
sending an error message to its host device. Data field is two bytes long.
Time base is 10 ms. Valid entries are 01 (10 ms) to FF FF hex
(10 min. 54 sec.). Default is 30 seconds.
Host-Reply Timer — Determines the amount of time a KFL or KFM
will wait for a supervisory reply message from its host device before
sending an error message to the remote station that sent the command.
Data field is two bytes long. Time base is 10 ms. Valid entries are
01 (10 ms) to FF FF hex (10 min. 54 sec.). Default is 20 seconds.