HMC Electronics MDL Series BK Precision DC Electronic Load System Module - Manual (Page 15)

15
Operations to Clear the OPP State
Check whether the input power is within the rated power range or the programmed protection
ranges. If it is outside the range, disconnect the device under test. Then press any key on the front
panel or remotely send command PROTection:CLEar. The OPP displayed on the front panel will
turn off and the electronic load exits OPP protection state.
Overtemperature Protection (OTP)
Each module has an overtemperature protection circuit, which will turn off the input if the internal
temperature exceeds safe limits. When the electronic load’s internal circuit temperature is over
85
 C, the load will enable OTP. Input will automatically be turned off and the VFD will display OTP.
At the same time the OT and PS bits in the status register will be set and remain until they are
reset.
Operations to Clear the OTP State
When the electronic load temperature has dropped below the protection point, press any key on
the front panel or remotely send command PROTection:CLEar. The OTP displayed on the front
panel will turn off and the electronic load exits OTP protection state.
Reverse Voltage Protection (LRV/RRV)
This function protects the electronic load in case the input DC voltage lines are connected with the
wrong polarity. When a reverse voltage (LRV – local reverse voltage, RRV – remote reverse voltage)
connection condition is detected, the input will immediately turn off, the buzzer will alarm the
user, and the status register’s reverse voltage (LRV/RRV) and VF bits will be set. The mainframe will
display LRV/RRV until they are reset.
In this condition, the 8-pin connector’s VF pin will output a high level. You can disconnect the
power supply via this signal (see Figure 31).
Operations to Clear the Reverse Voltage State
Check whether the connection is reversed. If so, disconnect the device to be measured and the
reverse voltage state will be cleared.
Documentation Provided By HMC Electronics
33 Springdale Ave. Canton, MA 02021
http://www.hmcelectronics.com
(800) 482-4440