Programming the Local Host
Chapter 5
54
Figure 5.2
Header Rung
L
027
07
022
00
077
G
030
G
Local
Node
Address of
Error Word
Supervisory
Timeout
Preset Code
011
G
TimeCritical
Timeout Preset
Code
Optionally a single GET will supply a single timeout
for both supervisory and timecritical.
The address in the three GET elements in the header rung specify (from
left to right):
The Address of The Error Word
The Supervisory Timeout Preset Code
The Time-Critical Timeout Preset Code
Select any available word in the data table as the error word. The
PLC-2/DHII interface will write error codes into the word you select
(refer to the “Error Word” discussion preceding Figure 5.12).
The timeout preset code gives a programmed timeout interval for
command completion. Based on the three-digit value entered for the
address in these GET instructions, the PLC-2/DHII interface monitors
command execution for all commands sent from the local node. The
significance of this preset code, its computation, and timeout
considerations are described in the discussion about “Timeout Preset
Value” (refer to Figure 5.23).
These are two timeouts. If you use two GET instructions, the first timeout
is for supervisory. The second GET is for time-critical. The timeout
preset for time-critical can be smaller, while the supervisory can be
generally larger. If you use only one timeout, it applies to both
supervisory and time-critical. Refer to the discussion “Programming
Preset Code” and Table 5.B which lists timeout preset codes.
