BOP-1K 031912 B-21FIGURE B-7. USING LIST:WAIT COMMANDS TO ALLOW AN EXTERNAL DEVICE TIME TOFUNCTION WHILE IMPOSING A MAXIMUM WAIT TIMENOTES: 1. The power supply is assumed to be operating in constant voltage mode.2. This example assumes a BOP and a DVM is connected to a Unit Under Test (UUT). The DVM isconnected to EXT_E/ EXT_C (pins 5/6 of the BOP External Protection port). When the BOP out-puts a low EXT_E/ EXT_C, The DVM takes a series of measurements and places its wait line low.The DVM Wait line is connected to the Trigger Input (pin 3 of the of the BOP trigger port). When theTrigger Input goes high (indicating the DVM has completed its measurements) the BOP willadvance to the next point. For this example it is assumed that the DVM will complete its measure-ment within 25 mS to 75 mS unless a problem is encountered. A “dead man” timer is implementedthat allows up to 99 mS for the measurement to complete before automatically proceeding to thenext point, thereby preventing hang-ups due to a measurement problem.3. The explanation below shows how each step of the list functions once the list is entered andVOLT:MODE LIST (the last step) is executed.LIST:CLE Clear list.LIST:SET:WAIT .0333 Set wait time to max allowed value (33 mS).LIST:SET:TRIGGER .001,ON Set trigger pulse width to 1 mS. Transistor across pins 5 and 6 of Exter-nal Protection Port is now set off.LIST:VOLT:APPLY LEVEL,.001,10 Create first point (10V).LIST:DWELL:POINTS? Returns 10.LIST:TRIGGER 10 Maintains output at 10V, generates a 1 mS 0V trigger pulse applied toDVM, causing DVM to make measurement.Trigger input low while DVM makes measurement.LIST:WAIT:HIGH 10 Wait for DVM to complete measurement for 33 mS. Proceed to nextstep if trigger input goes high (meaning the measurement is complete)or 33 mS elapsed, whichever comes first.Trigger input low while DVM makes measurement.LIST:WAIT:HIGH 10 Wait for DVM to complete measurement for another 33 mS. Proceed tonext step if trigger input goes high (meaning the measurement is com-plete) or 33 mS elapsed, whichever comes firstTrigger input low while makes measurement.LIST:WAIT:HIGH 10 Wait for DVM complete measurement for another 33 mS (these threesteps allow a maximum wait time of 99 mS. Proceed to next step if trig-ger input goes high (meaning the measurement is complete) or 33 mSelapsed, whichever comes first.LIST:REPEAT 10,13,20,30,40,50,60,70,80,90Repeats steps 10 through 13 (from list:apply level to the thirdlist:wait:high 10) for the other 8 voltages (20, 30, . . . 90).LIST:COUNT 10 Repeat sequence ten times.CURR 2;:OUTP ON Establishes BOP output current of 2A.VOLT:MODE LIST Executes the above list. A level is applied to the BOP output. One 1 mSlater the transistor at EXT_E and EXT_C (pins 5 and 6 of the ExternalProtection Port) conducts, providing a low to the DVM. The DVM imme-diately places the BOP trigger input low. The BOP waits for the triggerinput to go high, then outputs the next level in the list. If the trigger inputnever goes high, the three wait statements will maintain the level for 33mS each. After 99 mS (three wait statements) has expired, the newvoltage level will be provided at the output. In this example, the pulsemust be less than 1 mS. but at least 50 μS long to insure proper opera-tion of the program.
