Gossen Metrawatt GmbH
15
2.3.3
Constant Resistance Mode (CR)
Constant resistance mode has three ranges: the low range (CRL), the medium range (CRM), and the high range (CRH). In CR mode,
the load is equivalent to a constant resistance and will sink a current linearly proportional to the input voltage in accordance with the
programmed resistance to make I=U/R (see Fig.2-3). Press
key in basic mode to enter into mode selection and parameter set-
ting menu. Choose CR mode with
▲
and
▼
keys. Input the resistance value via the Entry keys or the knob and with
◄
and
►
keys.
Use
Enter
key for confirmation. The CR mode and parameters can also be set via remote command (MODE CRL, MODE CRM, MODE
CRH, RESistance <NRf+>).
Figure 2.3
Constant Resistance Mode (CR)
2.3.3.1
Setting Ranges
Constant resistance 80 V models
low value range (CRL) = 0.02 ... 2
Ω
,
medium value range (CRM) = 2 ... 200
Ω
,
high value range (CRH) = 20 ... 2000
Ω
.
Constant resistance 200 V models
low value range (CRL) = 0.0666 ... 6.66
Ω
,
medium value range (CRM) = 6.66 ... 666
Ω
,
high value range (CRH) = 66.6 ... 6660
Ω
.
Each time the setting range is changed while the load‘s input stays in ON status, the load will be turned off for around 5 milliseconds.
For example, when the load is switched from CRL to CRH, the input will be turned off around 5 milliseconds. Besides, it is noted that
the resistance setpoint may change with the resistance range to fit the new range.
Example: the present setting is CRM 10.000
Ω
, when the load is switched from CRM to CRL, the resistance setpoint will change to the
maximum level 2.0000
Ω
for CRL.
2.3.3.2
Immediate Resistance Level
The immediate resistance level refers to the resistance setpoint value in CR mode, which can be set via mode selection and parameter
setting menu, or via remote command (RESistance <NRf+>). The immediate resistance level can also be modified directly with the
◄
►
keys and the knob in CR mode.
2.3.3.3
Triggered Resistance Transition
The triggered resistance transition refers to the preset resistance setpoint value, which can become immediate resistance setpoint
value automatically when a trigger is received. If the CR mode and the input are enabled, the input will be updated immediately when a
trigger occurs. If the CR mode is not active, this resistance level will have no effect on the input until the CR mode becomes active.
The triggered resistance level only can be set via remote command (RESistance:TRIGgered <NRf+>). Once a resistance level is trig-
gered, subsequent triggers will become invalid until another (RESistance:TRIGgered <NRf+>) command is received. The trigger opera-
tion will be described in later chapter. The status register of the electronic load can keep track of pending triggers and other operating
conditions, which will be described in details in the “SPL SCPI Programming Guide”.
2.3.3.4
Transient Resistance Level
The load will switch between the transient high resistance level (LevelH) and transient low resistance level (LevelL) when the transient
operation is enabled. The transient resistance level can be set in transient operation menu from the front panel, or via remote command
(RESistance:HIGH<NRf+>, RESistance:LOW <NRf+>).
Input Current
Input V
o
ltage
(Resistance
Setpoint)
Slope
V
I
