10
GOSSEN METRAWATT GMBH
7
Current Source and Current Sink
➭
Connect the device under test with the measurement ca-
bles.
➭
Select the mA current sink
calibration function or
mA current source
with the rotary switch.
➭
Press
Esc
until you enter the range selection menu.
➭
Select the desired range:,
0
…
20 mA, 4
…
20 mA or 0
…
24 mA,
with the
#"
keys.
➭
Press the
↵
key to enter the output menu.
➭
Setting the simulation value:
The decade (i.e. the position of the digit to be changed) is
selected with the
$
!
keys, and the respective digit is
set with the
#"
keys.
ON
indicates that the current source is active.
7.1
Current Sink – Simulation of a 2-Wire Transmitter
A current sink (0
…
24 mA) or current loop load can be simu-
lated with this function. The calibrator regulates the current,
which flows via the calibrator jacks from an external power
supply, independent of direct voltage applied to the jacks
(4
…
27 V). The caliibrator varies the internal resistance such
that the adjusted current value flows.
Note!
☞
The latest adjusted simulator range is stored to mem-
ory. Voltage at the calibrator jacks may not exceed
27 V in the current sink operating mode, because
thermal overload would otherwise occur and the fuse
F3 would blow.
LoVolt
appears at the display where the voltage is too
low.
Example of a 2-Wire Transmitter Measuring Circuit
7.2
Current Source
Internal supply power is used for the simulation of a current
source.
Note!
☞
The internal control circuit of the current source is
monitored: if voltage drops by more than 20 V at the
external burden or if the current circuit is interrupted,
„Hi burd“ appears at the display.
Attention!
!
In this operating mode interference voltages must not
be applied to the calibrator jacks.
In the event of operating errors, such as the short-
term application of a high interference voltage, the in-
strument/calibrator is protected by a replaceable
fuse F3, see chapter 12.3.
Simulation in Percentages (current source only)
➭
Select the simulation function and the output range
(Isink/Isource = 4
…
20 mA) with the rotary switch and
the
#
key.
➭
Press the
ESC
and
#
keys simultaneously.
13
.
452
NUM
ON
SINK
mA
4-20
m A
4-20
NUM
sele t
range
m A
#"
Current
#"
Current Value
Range
$
!
ON
SINK
SINK
Range Selection Menu
↵
ESC
(... 2x)
Peripheral Device
24 V
Power
4 ... 20 mA = 0 ... 100
°
C
+
+
–
–
Pack
CALIBRATOR
–
+
Output
13
.
452
NUM
ON
SOURCE
mA
0-20
m A
0-20
NUM
sele t
range
m A
#"
Current
#"
Current Value
Range
$
!
ON
SOURCE
Range Selection Menu
↵
ESC
(... 2x)