Up to 64 Sampling Groups can be set in the system.
The maximum number of data item (number of addresses) that can be sampled at one time is 512 for 16 bit length, and 256 for 32 bit length.
Addresses or internal device addresses for one device/PLC unit can be set up to one sampling group. You cannot set addresses from multiple devices/PLCs, or set device/PLC addresses and internal device addresses.
The number of samples you can have in a sampling group (or Occurrences x Number of Blocks) depends on the [Mode] tab's [Backup to Internal Memory] selection*1, the number of data per sample (number of addresses), data length, and the operation mode.
See the following for more details. 
24.11.1.1 Usage Capacity of Sampled Data
When you use a display unit with 320 KB of SRAM, the estimated number of samples you can save is as follows.
When using one sampling group
|
Specified Addresses |
Data Length: 16 bit |
Data Length: 32 bit |
|
1 |
81,332 |
81,332 |
|
16 |
10,166 |
5,082 |
|
64 |
2,540 |
1,270 |
|
256 |
634 |
316 |
|
512 |
316 |
- |
(The number provided is the estimate calculated from the backup SRAM capacity. The maximum number of samples you can have in one sampling group is 65535.)
To check the capacity, go to the [Project (F)] menu, point to [Information (I)], select [Project Information (I)], and then select [SRAM Information].
After the display unit is powered ON and the internal programs are prepared, a one second maximum delay may occur before the sampling starts.
If a large amount of data is set to be sampled in a short cycle, then display updates and screen changes will slow down and the communication cycle time*2 will increase. In this case, because the next sampling occurs before reading data from the device/PLC, the previous data is treated as that round's sampling data.
For the Execution Condition - [Constant Cycle], [Constant Cycle when Bit is ON], and [Bit Change], because all the set address data is being read, the communication may put a burden on the system if the number of addresses to sample is large.
If the Execution Condition is [Constant Cycle], or [Constant Cycle when Bit is ON], even if the [Sampling Cycle] is longer than the communication cycle time, the communication cycle time*2 may exceed the [Sampling Cycle], due to a screen change or scroll display. In that case, because sampling occurs before reading data from the device/PLC, the previous data is treated as that round's sampling data.
When the [Sampling Cycle] is short (1 to 2 seconds, or 100 milliseconds), and a large process occurs such as a screen change, sampling will be unavailable for a set period of time. As shown above, the previous data will be displayed as that round's data.
If [Random] is selected in [Address], it will take longer to communicate with the device than when [Sequential] is selected.
When [Random] is selected in [Address], you cannot set a symbol variable to the address.
When creating multiple sampling groups with the bit ON setting as the execution condtion, specify a different address for the ACK Bit Address. If the same address is specified, bits will not be turned ON and OFF correctly.
When backing up sampling data in SRAM to a CF Card/USB Storage.
Set up the [Sampling Cycle] x [Occurrences] setting to be longer than 5 seconds if [Use Memory Card As Backup Area] is selected. If saving to the CF Card/USB Storage occurs within one second, the data will not save successfully because the backup data file (binary) is duplicated. If data is backed up in multiple sampling groups, the data may not save correctly depending on how often data is saved.
The name of backup files (binary) is automatically generated by adding an index number from 0 to 9 to the time stamp (year/month/day/hour/minute/second). Up to 10 files can be created with the same time stamp. If there are more than 10 files, a write error occurs and new files are not saved.
*1 To store sampling data in the backup SRAM, select the [Backup to Internal Memory] check box in [Mode]. To store the data in the DRAM, clear the check box. You can change the storage option for each set of sampling data.
*2 The Communication Cycle Time is the time it takes from the point the display unit requests data until the display unit receives data from the device. It is stored in the internal device LS2037 in Bin format. The unit is 0.1 ms.
When using multiple devices/PLCs, you can check the communication cycle time of each by using the internal device addresses set up from the [System Settings] window's [Peripheral List] page, in the [List of Device/PLC Management Addresses] area.5.19.13 Peripheral List Settings Guide