3-18 BOP HIPWR 031912capable of delivering ±28A in current mode can be configured to allow current to be adjustedfrom –0.5A to +10A by setting –Current Min to –0.5 and +Voltage Max to +10. Adjustmentrange is between 0 and E Onom for voltage and 0 and I Onom for current. Note that these soft-ware limits are not the same as the Protect Limits described in PAR. 3.3.4.2.The main channel software limit values can be lowered (closer to zero) by the user, e.g., to pre-vent inadvertent damage to a specific circuit under test. When the maximum/minimum valuesare lowered, the unit will not accept values that exceed the new software limits. If the userattempts to enter a value that exceeds the software limit, the unit will continue to function. inlocal mode the Exceeding Maximum Allowed Value message is displayed, and the outputwill be clamped to the main channel software limit (maximum/minimum) value. In remote modethe command is considered invalid and is disregarded: a 120 error is produced and the mes-sage Voltage Out of Range or Current Out of Range is displayed on the front panel.The main channel software limits are always in effect, even when the unit is controlled by anexternal reference. If main channel software limits are changed from the default, the pro-tection limits must be changed to correspond to the new software limits (see PAR.3.3.4.2). As an example, changing +Voltage Max and –Voltage Min of a BOP 36-28MG to ±3V,respectively, causes the unit to behave as if it was a BOP 3-28MG. In this case it is important tochange the +V Protect Max and –V Protect Min limits (e.g., to ±3.3V, respectively) so that theload is protected when operating in Current Mode.1. Press % from the power-up screen to enter the General Setup menu, then highlightMax/Min Settings.2. Press ! to enter the Max/Min Settings submenu (Figure 3-7 and Table 3-5). (If a Passwordis required, see PAR. 3.2.4.4 for instructions.)3. Highlight the voltage or current max/min value and press ! to change it. Software limitsare absolute values (do not use minus sign for negative limits). Use number keys to changethe setting, then $ to save.4. When complete, press $ to save for power-up, # to abort, or % to apply the changes(without saving for power-up) and exit.5. Upon return to the power-up screen, the main channel (voltage or current) is comparedagainst the main channel limits in effect. If the main channel exceeds the limit, it is set tozero.3.3.4.2 CHANGING MAXIMUM/MINIMUM PROTECTION SOFTWARE-CONTROLLED LIMITSThe ± protection limits are software limits that establish the maximum and minimum (maximumnegative) allowable levels of output voltage in current mode and current in voltage mode. Thedefault protection limits are 1% above E Omax or 1% above I Omax .The protect channel limits are +V (voltage) Protect max, –V Protect min, +C (current) ProtectMax and –C Protect min (see Table 3-4); these prevent the unit from delivering voltage or cur-rent that exceed these settings. In voltage mode the current protect channel is clamped to thelimit value; in current mode the voltage protect channel is clamped to the limit value. Adjustmentrange is between a minimum (box) value (see Figure 1-3) and 1% above the nominal (rated)value.
