Appendix: HART Specific Information
MSA
ULTIMA X ® Series
GB
99
Host Interface
Analogue Output
The three-wire 4-20 mA current loop is connected on terminals marked
8-30 VDC [1], 4-20 mA OUT[2], and GND [3-wire] [3]. The two-wire 4-20 mA cur-
rent loop is connected on the 8-30 VDC[1] and 4-20 mA OUT[2] terminals. Refer to
the installation outline drawings for details.
This is the main output from this transmitter, representing the process gas meas-
urement, linearised and scaled according to the configured instrument range. This
output corresponds to the Primary Variable [PV]. HART communications are sup-
ported on this loop. This device has a Capacitance Number [CN] of 1.
An inoperative device can be indicated by down-scale or up-scale current, depend-
ing on the sensor type. Current values are shown in the following table:
Current Values
Direction
Values [% of Range] Values [mA or V]
Linear over-
range
Down
Up
0%
+105.0% +1.0%
4.00 mA
20.64 to 20.96 mA
Device malfunc-
tion indication
Down: less than
Up: greater than
3.5 mA
20.96 mA
Maximum cur-
rent
22.0 mA
Multi-drop Cur-
rent draw
3.5 mA
Lift-off voltage,
3-wire PCBA
8 VDC
Lift-off voltage,
2-wire PCBA
13 VDC at 250 Ohms
