HT instruments HT8100 - Manual (Page 11)

HT8100
EN - 10
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) Range 0-20mA Range 4-20mA
0% 0mA 4mA
25% 5mA 8mA
50% 10mA 12mA
75% 15mA 16mA
100% 20mA 20mA
120% 24mA Not available
125% Not available 24mA
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.
mA
 Output DC current with automatic ramp as indicated in Table 3
Ramp type Description Action
Slow linear ramp Passage from 0% 100% 0% in 40s
Quick linear ramp Passage from 0%
100% 0% in 20s
Slow step ramp 0% 100% 0% with ramps of 15s
Quick step ramp 0%
100% 0% with ramps of 5s
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.