Honeywell IAQPoint2 User Manual page 679

Annex A
301ADI/420MDBS Technical Bulletin
There is also a basic Raw Unit* conversion formula for non-standard 0 -
20 mA devices:
(Loop current) x (range maximum - range minimum) +
(28 mA** - 0 mA) x (specified factor)
In this formula, there is no 4 mA offset, which enable the controller to
read devices that do not adhere to the 4-20 mA standard. Note that, in
this mode, no fault will be generated for signal readings below 3 mA
(for 301ADI) or below 1 mA (for 420MDBS).
*Raw units represent the following measurement types: mA, mV, V and
no units.
** The mA range for the 301ADI is 28 mA to 0, however, the range for
the 420MDBS is 25 mA - 0 mA.
Special notes for 301ADI and for 301C (firmware version 2):
301C Event menu: Measurement units other than PPM for all 4-20
inputs (identified as AI) will be displayed as %, however the selected
value will be correct and the even will function normally (as shown in
the menu samples below).
3. Events
Tx097
> 25.0%
It is not possible to program an event using a negative value with this
version of the firmware.
24
001 1.
Factor
Units
301ADI User Manual
Honeywell
Tx Info 097
-Scale(2)-
00001
mA
range minimum
specified factor
510846
4/07