Article - CS333290
U-CON Driver: What Are the Differences Between Scratch, Rolling, and Global Buffers?
Modified: 02-Nov-2020
Applies To
- Kepware Server (formerly KEPServerEX) 5.19.467.0 to 6.8
- ThingWorx Kepware Server (legacy) 8.0 to 8.4
Description
Descriptions of the buffers are as follows: Scratch Buffers: Each device is associated with 256 Scratch buffers, which exchange information between transactions defined for a device. The data stored in a Scratch buffer will exist as long as the OPC server project is running (or until the Scratch buffer is overwritten in a transaction). Rolling Buffers: Each device is associated with one Rolling buffer, which exchanges information between transactions defined for a device. Rolling buffers are similar to Scratch buffers, but differ in that writes append data instead of replacing it. Data stored in a Rolling buffer will exist as long as the OPC server project is running (or until the Rolling buffer is overwritten in a transaction). Global Buffers: There are 256 Global buffers, which exchange information among devices. Each Global buffer is associated with all devices under every channel. Note: Data cannot be copied to Scratch or Rolling buffers associated with different devices.
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