Pressure - What is the response time of a Pressure Transmitter?

Response Time

Response Time is the amount of time (in seconds) it takes for the output signal to reach 63.2% of an instantaneous full-scale pressure change. Pressure transmitters respond to pressure changes as a first-order system; therefore, derived from an equation used for modeling exponential decay rates, the 63.2% figure represents the output change for the first time constant. An excellent technical definition that does not mean much to us.

In the real world, Response Time consists of two components, Dead Time and Time Constant. It can be expressed in the following equation.

RTt = Td + Tc

Where,

RTt  = Total Response Time

Td = Dead Time - The amount of time for the transmitter to initially respond to the change in pressure.

Tc = Time Constant - mechanical response time (MRT) + electronic response time (ERT)

Yokogawa pressure transmitters with Hastelloy C-276 diaphragms (Yokogawa’s base diaphragm material) have a response time of 90 ms (including a dead time of 45 ms); making Yokogawa’s pressure transmitters one of the fastest smart transmitters on the market.

Refer to FieldGuide FGP-140 Pressure Transmitter Response Time for more detail.