Scan Time Interval is the frequency of polling requests for new data. Displayed as Seconds. (Note that it is specified in Milliseconds in the WebAccess Project Manager). Engineers and technicians set the scan time when configuring the communications port the device uses. The speed is largely determined by the PLC or field device and the nature of the network (how many other devices there are, how much data, the protocol, and baud rate). Slower the baud rates and the larger the amounts of information, require slower scan times. Refer to the Device Manufacturer's Manual for information on minimum scan times.
The freshness of the data is largely determined by the protocol, some protocols are report by exception and include Deadbands that must be exceeded before a value is updated.
A zero (0) sets the scan time to scan as often as possible.
0 to 3600
Field Type: Analog
Tag fields: .SCANTM read only