Rockwell Automation 1771-KA2 Communication Adapter Module - Manual (Page 89)

Command Initiation, Execution, and
Monitoring
Chapter 7
7-17
If it is necessary to use a value other than those provided in Table 7.B,
compute the 3-digit timeout preset code as follows:
1. Select a timeout preset interval. This interval must be at least one
second.
For the purpose of computing the code, label this number “S.”
EXAMPLE: desired interval = 7 seconds = S
2. Compute a decimal (base 10) number using the desired interval of
step 1 in the following formula:
S + 8
EXAMPLE: S + 8 = 15
3. Convert this value to a 3-digit octal (base 8) value.
EXAMPLE: 15
10
= 17
8
For a brief description of decimal-to octal conversion, refer to chapter 13
of publication 1772-821, Programming and Operations Manual,
Mini-PLC-2 Programmable Controller. You can disable the timeout by
using the value 010.
User-Programmed Timeout (Optional)
The automatic timeout of a 1771-KA2 communication adapter module
has a backup function. This automatic monitoring routine continuously
checks module interaction with other Data Highway stations, timing the
execution of commands. This automatic timeout does not check module
communication with its own station processor. For a backup check on
module/processor communication, an optional programmed ON-DELAY
timer instruction (TON) can be used.
With proper module/processor communication, the module sets either a
DONE bit or a REMOTE or LOCAL FAULT bit as a response to a
command. However, in the event of faulted module/processor
communication or faulted module operation, a response bit might not be
set. Instead, the START bit would remain on in this instance until the
fault situation was corrected. Several programming methods can be used