Gossen Metrawatt GmbH
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All errors are saved in one error queue. The errors in this error queue are read in the order in which they occurred. At most 20 error
messages can be saved in the error queue. If the errors exceed 20, the last error in the error queue will be replaced with -350, “Too
many errors”. The load will not save any additional error message, unless you clear or read errors from the queue. Once the error mes-
sage is read, it will be cleared in the error queue.
2.13
Status Report
The electronic load incorporates a status reporting register. Various status conditions of the load can be reported by querying the sta-
tus register. The user can make sure which event has been reported through setting the enable register, which will be introduced in
detail in the SPL SCPI Programming Guide.
2.14
Protection Function
The electronic load is equipped with the following protection functions:
•
Overvoltage (OV)
•
Overcurrent (OC)
•
Overpower (OP)
•
Overtemperature (OT)
•
Reverse Voltage (RV)
Once any of the above protection function is active, the corresponding status bit in the status will be set; the input will be turned off
with beeps; the detected conditions will be displayed; the load will enter into the latched protection status, and will not respond to other
commands except some specific operations. For example: if an overtemperature condition has been detected, the input will be turned
off with beeps, and OT will be shown in the lower right corner of the display. The load will have no response to other operations.
2.14.1 Clearing Latched Protection
When the load enters into the latched protection status, it will have no response to other commands. The load will return to the normal
operation only when the latched protection has been reset via pressing
key +
key or the remote command (INPut:PROTec-
tion:CLEar). The condition that causes the latched protection must be removed, or it will be latched again as soon as it is reset.
In addition, when the software overcurrent protection is enabled, if the overcurrent time does not exceed the specified protection time,
the load will display PT to indicate, but the input will not be turned off. At this time, you can reset the overcurrent time with
key
+
key or the remote command (INPut:PROTection:CLEar).
2.14.2 Overvoltage
The overvoltage protection level is set at a predetermined voltage, which cannot be changed by the user. When the input voltage
exceeds this predetermined voltage, the overvoltage protection will be enabled, and the input is turned off with OV displayed, mean-
while, the OV and VF status register bits are set, and will remain set until they are reset and the overvoltage condition is removed.
2.14.3 Overcurrent
The electronic load allows the user to define a current protection limit. When the defined current limit is exceeded, the overcurrent timer
starts timing, and the display will show PT to indicate protection status, but the input will not be turned off immediately. When the spec-
ified delay time is reached, the overcurrent protection will be enabled and the input is turned off with OC displayed, meanwhile, the OC
and PS status register bits are set, and will remain set until they are reset and overcurrent condition is removed. The current protection
limit function can only be set via the remote command. The function is activated or deactivated via command (CURRent:PROTec-
tion:STATe ON/OFF). The setpoint value for overcurrent protection can be set via command (CURRent:PROTection < NRf+>). The
delay for turning the load input off can be set via command (CURRent:PROTection:DELay < NRf+>).
2.14.4 Overpower
The electronic load includes both hardware and software overpower protection functions.
Once the input power exceeds the maximum rated power, the hardware power-limit circuit will be enabled without delay to limit the
input power within the allowed range, in the meantime, the load will compute the present input power.
No matter whether the hardware power-limit circuit is enabled or not, the software overpower protection will become active as long as
the overpower time exceeds the specified limit. When the overpower protection is enabled, the input will be turned off with OP dis-
played, meanwhile, the OP and PS status register bits are set, and will remain set until they are reset and overpower condition is
removed.
2.14.5 Overtemperature
If the internal temperature of the load exceeds safe limits, the overtemperature protection will be enabled; the input will be turned off
with OT displayed, in the meantime, the OT and PS status register bits are set, and will remain set until they are reset and overtempera-
ture condition is removed. You must wait until the load cools down to the normal temperature before you can reset the latched protec-
tion. The fans in the load will help to cool the load as quickly as possible.
2.14.6 Reverse Voltage
When reverse voltage is applied, the reverse voltage protection will be enabled; the input will be turned off with RV displayed, in the
meantime, the RV and VF status register bits are set, and will remain set until they are reset and reverse voltage is removed.
