What is the voltage range accepted by SMAR transmitters?

First we need to divide the answers for the line of HART transmitters and other for the FOUNDATION and PROFIBUS PA transmitters.

HART transmitters

This is a classic graphic to understand the Power Supply minimum output value related to the total load of the line.

We can see above that if the load is 250 Ohm then the minimum voltage for the Power Supply is 17 Volt. The maximum will always be 45 Volt.

Of course if the load of the line increases the minimum voltage for the Power Supply will also increase. We should always use a voltage value above the minimum value.  Most typically 24 V and 32 V power supplies are very popular.

FOUNDATION and PROFIBUS PA transmitters

The load for these lines are typically the resistance added by the network cable itself.  That, consequently, makes the added load relatively small.  Best way is to have in mind that it is expected to see a voltage between 9 – 32 VDC at the SMAR FOUNDATION and SMAR PROFIBUS PA transmitter terminals.

Same thing here, a power supply that can hold voltage around the 24 V will make a good choice.

It is also good to know that SMAR FOUNDATION and PROFIBUS transmitters have a quiescent current consumption of 12 mA.

For these 2 protocols, noise and ripple should fall within the following limits:

a) 16 mV peak to peak from 7.8 to 39 KHz.
b) 2 V peak to peak from 47 to 63 Hz for non-intrinsic safety applications and 0.2 V for intrinsic
safety applications.
c) 1.6 V peak to peak from 3.9 MHz to 125 MHz.