Siemens S7-1200 System Manual page 219

Assign a multi-instance DB to store timer data as retentive data
This option only works if you place the timer in an FB.
This option depends upon whether the FB properties specify "Optimized block access"
(allows symbolic access only). To verify how the access attribute is configured for an existing
FB, right-click on the FB in the Project tree, choose properties, and then choose Attributes.
If the FB specifies "Optimized block access" (allows symbolic access only):
1. Open the FB for edit.
2. Place the timer instruction at the desired location in the FB.
3. When the Call options dialog appears, click the Multi instance icon. The Multi Instance
4. In the Call options dialog, rename the timer if desired.
5. Click OK. The timer instruction appears in the editor, and the IEC_TIMER structure
6. If necessary, open the FB interface editor (may have to click on the small arrow to expand
7. Under Static, locate the timer structure that was just created for you.
8. In the Retain column for this timer structure, change the selection to "Retain". Whenever
If the FB does not specify "Optimized block access", then the block access type is standard,
which is compatible with S7-300/400 classic configurations and allows symbolic and direct
access. To assign a multi-instance to a standard block access FB, follow these steps:
1. Open the FB for edit.
2. Place the timer instruction at the desired location in the FB.
3. When the Call options dialog appears, click on the multi instance icon. The multi instance
4. In the Call options dialog, rename the timer if desired.
5. Click OK. The timer instruction appears in the editor, and the IEC_TIMER structure
6. Open the block that will use this FB.
7. Place this FB at the desired location. Doing so results in the creation of an instance data
8. Open the instance data block created when you placed the FB in the editor.
9. Under Static, locate the timer structure of interest. In the Retain column for this timer
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
option is only available if the instruction is being placed into an FB.
appears in the FB Interface under Static.
the view).
this FB is called later from another program block, an instance DB will be created with this
interface definition which contains the timer structure marked as retentive.
option is only available if the instruction is being placed into an FB.
appears in the FB Interface under Static.
block for this FB.
structure, check the box to make this structure retentive.
Basic instructions
7.2 Timer operations
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