Appendix: HART Specific Information
MSA
ULTIMA X ® Series
GB
131
13.9 Performance
Typical sampling rates are shown in the following table.
Sampling Rates
Power-Up
On power-up, the transmitter goes through a self-test procedure, and a sensor
warm up and initialisation period which takes approximately 30 seconds. During this
period, the device will not respond to HART commands, and the analogue output is
set at 3.75 mA.
When the self-test is satisfactorily completed, and the sensor initialised, the PV va-
lue is set, and the analogue output moves to a value representing the measure-
ment. The rate of this calculation is limited by an internal filter damping time. Only
after the PV and SV are correctly set, will the device respond to HART commands.
If the self-test fails, all live measurement data [PV, current and percent of range] are
set to "Not A Number", and the analogue output is set to the configured malfunction-
indicating current. The device will attempt to respond to HART commands.
Fixed-current mode is cancelled by power loss.
Reset
Command 42 ["Device Reset"] causes the device to reset its microprocessor. The
resulting restart is identical to the normal power-up sequence.
Gas Samples
4 per second
PV digital value calculation
5 per second
Analogue output update
5 per second
