Output Dc Current Generation; Loop Power And Hart 250 Modes - Ht Instruments Ht8100 Bedienungsanleitung

4.3.7. Output DC current generation

The "OUTPUT" section of the function selector switch defines the possibility of generating
an output DC current with the instrument, considering the selectable measuring ranges 0-
20mA or 4-20mA. The instrument may operate in the following modes:
DC current source → DC current generation (see § 4.4.7).
Simulation → simulation of a transducer in a current loop with auxiliary power supply
(see § 4.4.8)
The positions of the rotary switch are the following:
mA → Output DC current, which may be selected as indicated in Table 2
Percentage value (% STEP)
0%
25%
50%
75%
100%
120%
125%
Table 2: Selectable values of output DC current
Output current adjustment is possible with the options:
➢ %STEP → setting of values 0%, 25%, 50%, 75%, 100%, 120%, 125% of the selected
range.
➢ Quick adjustment → setting of values 0%, 50%, 100% of the selected range.
➢ FINE → setting of custom values in the range 0 ÷ 24mA with resolution of 1µA.
→ Output DC current with automatic ramp as indicated in Table 3
mA
Ramp type Description
Slow linear ramp
Quick linear ramp
Slow step ramp
Quick step ramp
Table 3: List of available ramps for output current
4.3.8. Loop Power and HART 250 modes
In the LOOP POWER function, the instrument is capable of generating an output voltage >
24V DC to supply an external transducer and directly measure the corresponding loop
current.
The HART 250 function allows setting a 250 internal resistor for loop measurement on
transducers operating with HART (Highway Addressable Remote Transducer) protocol.
Range 0-20mA Range 4-20mA
0mA
5mA
10mA
15mA
20mA
24mA
Not available
Action
Passage from 0% →100% →0% in 40s
Passage from 0% →100% →0% in 20s
0% →100% →0% with ramps of 15s
0% →100% →0% with ramps of 5s
EN - 10
HT8100
Commentato [a2]: 4.4.8
4mA
8mA
12mA
16mA
20mA
Not available
24mA