User`s guide

Page 33

Controlinc 1746-C (Version 5.21) Network Master Users Guide (2004-11-18)

5. System Tables

From the perspective of the PLC, all tables can be read but only some can be written to. If the PLC

attempts to perform a write to a “read-only” table, the 1746-C ignores it and treats it as a read

command/request.

In general, when writing data to be transmitted to the actuators over the network, the Network Master

will differentiate which values change in tables being received from the PLC and will only send new

command information to the actuators that require a change.

The tables have the following PLC (“user”) access:

• Table [0]: read / write

• Table [1]: read only

• Table [2]: read only

• Table [3]: read / write

• Table [4]: read only

• Table [5]: read / write

• Table [6]: read only

• Table [7]: read only

• Table [8]: read / write

• Table [9]: read / write

• Table [10]: read / write

• Table [11]: read only

• Table [12]: read only

• Table [13]: read / write

• Table [14]: read / write

• Table [15]: read / write

• Table [16]: read / write

• Table [17]: read / write

• Table [18]: read only

• Table [19]: read only

• Table [20]: read / write

• Table [21]: read / write

• Table [22]: read / write

• Table [23]: read / write

• Table [24]: read / write

Table [0] is a “system focused” table. It is focused on information about the network system and

network master. All the rest of the tables are focused on information about individual actuator “units”.

NOTE: In tables [1  24 … except 15], the last 60 words hold information for particular actuators.

Words [4

 63] are in sequence with valve actuator network node addresses. A particular

actuator is represented by its

POSITION in the table as an offset starting from word [3] (the

end of the header). For instance, Word [7] in all tables will always have valve #4

information.