Tag Explorer¶
Tag Explorer is used to access individual variables inside controller memory.
Tag Explorer enabling access to variables from two different devices.¶
The Tag Explorer can be used to access variables from different devices. The data regarding each selected variable is shown in a separate row within a table. The dropdown list in the Variable Name column enables selection of the desired variable. For each selected variable, several properties are shown, including address, data type, etc.
The Type column indicates variable type. The variable type is used to properly interpret bit-streams comming from the device, and also for proper formatting of bit-streams which are sent to device. Variable type are typically loaded authomatically using compiler-produced variables description files. However, the user is free to change the type if he/she desires.
The user can initiate read operation for each variable by pressing the Read Tag button. The value obtained by reading is shown in the Read Value column. If the user wishes to change value of some variable, he/she should write the desired value in the Write Value column and press Write Tag button. Each time a user initiate write operation, a read operation will be issues automatically. Thus, the user need only inspect the Read Value field in order to see if the write operation has been successfull or not.
Clearly, the user will often want to change values of certain variables frequently. This is true, for example, for some controller parameters during fine-tuning of the closed-loop performance. In this case the need to click the Write Tag button each time would be cumbersome. In such cases, the user is advised to check the Automatic Write? check-box which ensures that a write request will be issued automatically (followed by a read request) as soon as the Write Value field is changed.
On the other side, there are some variables that must not be changed accidentally. In such cases, it would be nice to have some method of preventing any accidental write operation that migh occur. This is the reason for existence of the Read Only? check box. Once checked, no modification of the selected variable will be allowed.
