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Operation
D397-50-880 Issue C
4.9 Response time calculations & Measurements
The TIC & DX pump Profibus units response times (due to a change in output data) and true data update times vary
significantly depending on the data exchange configuration and the attached equipment. For both unit types there
is also a time delay due to the bus speed. For 9.6Kbd this is approximately 50ms. For 19.2Kdb it is approximately
25ms. For all other bus speeds the delay is relatively negligible.
For a DX pump Profibus unit on a high speed network, the response time on average is roughly:
120ms for the first software module
+ 30ms extra for each additional configured software module.
For a TIC Profibus unit on a high speed network, the response time on average is roughly:
30 ms
+ 30ms extra for each configured software modules with a 900 number
+ 140ms extra for each configured software modules with a 800 number
+ 50ms extra if a DX turbo pump is attached
+ 300ms extra if the measure of response time is gauge pressure update time.
Example: A TIC Profibus module fitted to a network operating at 19.2Kbd with a DX pump and 2 gauges fitted, with
the configuration 913, 914, 904, 860. To determine the likely average gauge update rate the calculation is
25ms (for bus speed)
+ 50ms (for Dx pump)
+ 30ms (fixed)
+ 3 x 30ms = 90 ms (for 900 modules)
+ 140ms (for 800 module)
+ 300ms (for gauge update time as the measure)
= 635ms
Note: The Sync and Freeze Profibus functions are supported by the TIC & DX pump Profibus units, but should be
used with caution due to the variable time delays associated with the units.
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