
Chapter 4
Basic Programming Techniques
4-8
Important Information on Outstanding Network Messages
You can establish up to 16 concurrent connections from your OSI
coprocessor. You are limited in the number of outstanding messages you
are allowed to have at one time. By outstanding messages we mean
messages that have had no response. You are allowed up to 32 outstanding
messages because that is what your PLC–5 controller allows at one time.
This limit applies to the total number of connections you have. There is
a limit of 5 outstanding messages per connection.
Note that even though your PLC controller supports up to 5 outstanding
messages per connection, the number you are allowed also depends upon
the device to which you are connecting. If, for example, you are
connecting to a device that supports only 2 outstanding messages per
connection, then you are limited to 2 for that connection (figure 4.4).
Figure 4.4
You are Limited in the Number of Outstanding Messages Allowed
OSI Network
Even though your Allen-Bradley
PLC controller supports up to 5
outstanding messages...
Outstanding messages
another vendor's MAP device
OSI Coprocessor
...if the device to which you are
connecting only supports 2
outstanding messages, you are
limited to 2 on this connection.
a connection
I - 12423
The following chart provides quick reference material on each of the
commands, including syntax rules and examples. Use this guide if you
have a thorough understanding of each of the commands. Refer to the
individual command sections for detailed information.
A Quick Reference Guide to
the Commands
Содержание PLC-5 MAP/OSI
Страница 1: ...PLC 5 MAP OSI Software User Manual Cat No 1785 OSI AB Parts...
Страница 4: ...Table of Contents iii OSI Layer Management E 1...
Страница 57: ...Chapter 4 Basic Programming Techniques 4 7 For example B7 6 10 AB Parts...
Страница 91: ...Mapping MMS Data Types onto PLC 5 40 5 60 File Types Appendix A A 2 T ACC D 16 AB Parts...