BOP HIPWR 031912 3-39maximum delay of 200 mS and the STANDBY indicator goes on. Depressing the STANDBY keyor sending the OUTP ON command via the remote interface restores the unit to the previousstate and the STANDBY indicator goes off.FIGURE 3-15. REMOTE STANDBY, STANDALONE OR MULTIPLE UNITS3.4.2 VOLTAGE/CURRENT MODE CONTROLThe mode of operation, voltage or current, can be programmed externally by applying a signalat pin 2, referenced to pin 9, of the Analog I/O port. Applying a TTL logic 1 (or open circuit) pro-grams the unit to voltage mode. Applying a TTL logic 0 (or short) programs the unit to currentmode.To be functional this feature must first be configured from the front panel. From the power-upscreen press $ to enter the Analog Remote Setup menu (see Table 3-15). Highlight ExternalMode, then press !, highlight Enable and press $. Press % to apply the changes (withoutsaving for power-up) and exit to the power-up screen or # to abort. The Save/Recall feature(PAR. 3.3.8) can also be used to restore this setting upon power-up.3.4.3 CONTROLLING THE OUTPUT USING THE BOP AS A POWER AMPLIFIERThe BOP can function as a power amplifier by means of the External Reference input at theAnalog I/O port. This analog signal controls the main channel of the BOP. To use the BOP as apower amplifier see the following instructions for using the external reference: PAR. 3.4.3.1 forfixed gain, PAR. 3.4.3.2 for variable gain by establishing the maximum full scale output.3.4.3.1 FIXED GAIN USING EXTERNAL REFERENCE CONTROLThe main channel of the BOP, voltage in voltage mode, and current in current mode, can becontrolled by an external reference voltage, 0 to ±10V applied at pin 11, referenced to pin 10, ofthe Analog I/O port. The input impedance for this signal is 20K ohms. This feature is enabled asfollows:1. From the power-up screen, press $, highlight Reference Input and press !. HighlightExternal and press $ to save. Then press % to apply the changes (without saving forpower-up) and exit. NOTE: This setting can be saved for power-up only by using the pass-word-protected Power-up Settings menu (see {PAR. 3.3.7), otherwise internal referencesare used for both main and protection channels upon power-up.
