User`s guide

76 DC 900-1317J
ADCCP NRM Programmer’s Guide
Word 2 in the data area contains the poll timer parameter value. This parameter is valid
only for NRM secondary stations and specifies the maximum number of seconds the
ICP waits to receive a constructive polling frame before reporting a station exception
(data poll timeout). A constructive polling frame is an I-frame, UI, RR, SREJ, or REJ
frame with the P-bit set to one; RNR frames are not considered to be constructive polls,
because they do not solicit data transfer from the secondary station. If the client does
not disable the station, then the ICP reports resumption of normal polling procedures
(when it occurs) as a station exception (data poll resumed).
Word 3 in the data area contains the flags timer parameter value; this parameter is valid
only for NRM secondary stations. It specifies the maximum number of seconds the ICP
waits to detect flags on the link before reporting a link exception (flags synchronization
lost). This timer is normally a long timer on the order of several minutes and is
intended as a means for detecting loss of a physical data link connection. Although this
timer is specified with the other station timers, each physical link has only one flags
timer; the last flags timer specified overrides all previous flags timer specifications for
stations on that link.
Word 4 in the data area contains the polling delay value. This parameter is valid only for
NRM primary stations and specifies the minimum number of milliseconds the ICP
delays between transmissions to the indicated remote secondary station. The client may
set a different delay value independently for each remote secondary station. This con-
trols the polling (and data transmission) loading for each secondary station on the link.
Values may range from 0 to 32767 milliseconds (inclusive) and may be tuned dynami-
cally while stations are active.
The first five words of the data area must contain either valid parameter values or a zero
value. If the client specifies any parameter with a value of zero, the ICP sets the param-
eter to its default value. Ta bl e 3 –9 shows the default value for each of the station param-
eters.