Advertisement
6 Programless Communications
6-3
Controlling Programless
Communications
The section describes the methods that are used to control programless communications from the PLC.
6-3-1
Controlling Programless Communications with the Request Flag
There are the following three ways to control programless communications. The Request Flag in PLC
memory is used to change the control method.
1. Updating Monitor Values (Disable Writing Request)
PLC memory
Response Flag
Communications Status
Upload
Area
Monitor Value
Request Flag: 0
Operation Command Code
Download
Area
Set Value
If you set the Request Flag to 0, the Response Flag will change to 0 and the monitor values will be updated.
2. Writing Set Values and Updating Monitor Values (Enable Writing Request)
PLC memory
Response Flag
Communications Status
Monitor Value
Request Flag: 1
Operation Command Code
Set Value
If you set the Request Flag to 1, the set values will be written to the E5@D and then the operation com-
mand will be written to the E5@D. Finally the Response Flag will change to 1 and the monitor values
will be updated. The operation command is processed only the first time, but the set values are written
each time. Therefore, you cannot change the parameters that are specified for download settings at the
E5@D. If you want to make the change in the E5@D, set the Request Flag to 0 to stop writing or refer to
6-2-11 Communications Writing.
3. Initializing the Download Area
PLC memory
Response Flag
Communications Status
Monitor Value
Request Flag: 2
Operation Command Code
Set Value
If you set the Request Flag to 2, the set values in the download area will be initialized to the values from
the E5@D and then the Request Flag and Response Flag will change to 1. Finally, the operation
described above for control method 2 is performed.
6 - 18
PLC memory
Response Flag: 0
Communications Status
Monitor Value
Request Flag: 0
Operation Command Code
Set Value
b. Monitor values are updated
PLC memory
and then "a" is performed.
Response Flag: 1
Communications Status
Monitor Value
Request Flag: 1
Operation Command Code
Set Value
a. The set values are
written to the E5@D.
PLC memory
Response Flag: 1
Communications Status
Monitor Value
Request Flag: 1
Operation Command Code
Set Value
The set values are initialized to the values in
the E5@D and writing is enabled.
E5@D Digital Temperature Controllers Communications Manual (H225)
The monitor values are
repeatedly updated.
Advertisement
