3-40 BOP HIPWR 0319122. To return to digital or local control, from the power-up screen press $, then highlight Refer-ence Input and press !. Highlight Internal and press $ to save. Then press % to applythe change and exit.NOTE: Each time the Reference Input setting is changed, the unit generates an internal *RSTreset command (see PAR. A.11) which requires the BOP output and/or protection limitsto be reprogrammed.When the external reference is used, the BOP functions as a power amplifier, amplifying theexternal reference at pin 11 to produce the output.The nominal (inherent) voltage gain of each model is calculated by (G NOM-V ) = E Onom / E REF.and nominal (inherent) current gain is (G NOM-I) = IOnom / E REF. Thus the nominal gain is the ratiobetween the nominal (rated) voltage or current (E Onom or IOnom ), and the external reference(E REF) used to produce that output.So for an external reference of ±10V, the nominal voltage gain (G NOM-V ) = E NOM-V /10, e.g., thevoltage gain of a BOP 36-28MG is 36/10 = 3.6. The nominal current gain (GNOM-I ) is INOM-V /10,e.g., the current gain of a BOP 36-28MG is 28/10 = 2.8.The external reference voltage may be d-c, a-c, or a combination of a-c plus d-c. The maximumfrequency of an a-c signal should be below the inherent frequency response of the BOP (2KHzfor voltage, 800Hz for current (see Table 1-2). For parallel or series combinations, the frequencyresponse is reduced as specified in the instruction manual included with the cable kit. A fre-quency that exceeds the bandwidth of the BOP will cause the output to be distorted.For linear response (input vs. output) the software limit (see 3.3.4.1) should be set to nominaland the maximum peak value (d-c plus a-c) of the reference signal must not exceed ±10V. If theTABLE 3-15. ANALOG REMOTE SETUP MENUSETTING CHOICES(BOLD = Factory Default) FUNCTIONREFERENCE INPUTPIN 11(referenced to pin 4)INTERNALEXTERNALEXTL REF LVLINTERNAL: Any external reference applied to the Analog I/O port pin 11 isignored and the output is controlled using either the local front panel keypad(see PAR. 3.3.2) or remote SCPI commands (see Appendix B).EXTERNAL: The external reference applied to Analog I/O port pin 11 is used tocontrol the output (see PAR. 3.4.3.1). The internal reference is ignored.EXTL REF LVL: Allows the gain of the BOP to be established by the maximumoutput voltage or current introduced in the main channel field. (see PAR.3.4.3.2).PROTECTION LIMITPINS 5, 6, 13, 14(referenced to pin 12)INTERNALEXTERNALLESSER LIMITINTERNAL - Allows the limits to be controlled by digital signals from either thekeypad (local, see PAR. 3.3.2) or SCPI command (remote, see Appendix B).EXTERNAL: Allows the limits to be controlled by analog signals applied to theanalog port; limits set from the keypad or SCPI command have no effect (seePAR. 3.4.4).LESSER LIMIT: Allows protect limit to be automatically selected from either 1)the external analog voltage applied to the Analog I/O port or 2) the value setfrom the keypad or SCPI command). Whichever limit has a lower absolutevalue (closest to zero) has effect .EXTERNAL MODEPIN 2(referenced to pin 9)DISABLEENABLEDISABLE - Allows the main channel (voltage or current) to be selected byeither the front panel MODE key or SCPI command. The condition of pin 2 ofthe Analog I/O port is ignored (see PAR. 3.3.2).ENABLE - The front panel MODE key and SCPI commands are preventedfrom affecting the active channel. Mode is determined by pin 2 of the AnalogI/O port (see PAR. 3.4.2). This function cannot be saved for power-up.NOTE: Power-up state for Reference Input and Protection Limit are established by Power-up Settings Menu (PAR. 3.3.7) underGeneral Setup Menu (Figure 3-6).
