Derivative units converter
Rate is derivative time. Some controllers count it in minutes, some in seconds. They are the same quantity, sixty apart. A 0.5 that meant minutes, typed into a field that expects seconds, is a factor-of-sixty error that still looks like a plausible number — the same class of bug as the reset-units mistake, without the reciprocal to make it obvious.
This converter handles both directions. It uses the same arithmetic PIDSnap uses when it phrases a rate change in your controller's units.
Which convention does my system use?
Common defaults, all of which should be confirmed on the actual block:
- DeltaV — minutes, matching RESET when the block is in minutes.
- Ovation — seconds.
- SIMATIC PCS 7 — seconds (TD).
- Rockwell PIDE — minutes in dependent form.
- Yokogawa Centum — seconds.
- Honeywell — minutes.
Why this is quieter than the reset trap
Reset has two extra ways to go wrong: repeats-per-time versus time-per-repeat, which run in opposite directions. Rate does not. Minutes and seconds of derivative time move the same way — a larger number is more derivative action in both conventions. The only error is the factor of sixty, and it is still enough to wreck a temperature loop.
Questions that come up
Does a higher rate number always mean more derivative?
Yes, in both minutes and seconds. Unlike reset, there is no reciprocal convention in common use. The conversion is a straight factor of sixty.
Related
These tools assume a self-regulating loop and a bump you have not shown us. Photograph the trend and the faceplate if you want a check against the loop in front of you, not a formula.
Last reviewed 2026-09-10.