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3-158
For example, assume the following commands are
sent to four power supplies assigned to addresses called PS1,
PS2, PS3, and PS4:
OUTPUT PS1; "HOLD ON; ISET 10A"
OUTPUT PS2; "HOLD ON; ISET 1A"
TRIGGER PS1
TRIGGER PS2
OUTPUT PS3; "HOLD OFF; ISET BA"
TRIGGER PS3
OUTPUT PS4; "HOLD OFF; ISET 5A''
Power supply 2 will start to change only after power supply 1
has started to change, and power supply 4 will start to change
only after power supply 3 has started to change. Note that this
feature concerns only the processing of the HP-IB command,
the time required for the power supplies to settle at their new
values depends on the load and on the direction and amount
of change.
3-159
Store/Recall. The power supply can store up to 16
complete power supply states except for output on/off. This
allows the operator to preset frequently used values, which can
then be recalled when needed with a single command. Preset
values are stored and recalled using these codes (3 and 11 us¬
ed as examples):
STO 3
RCL 11
3-1®3
Sending a store command causes a "snapshot" of
the present machine state to be stored. The power supply can
then be programmed with new values. Note that only those
values to be changed need be reprogrammed. For example, if
the following command strings were sent in listed order to the
power supply, the string stored in register 1 would include a
current setting of 2A and CC foldback in addition to a voltage
setting of 8V. The string stored in register 2 would include a
voltage setting of 8V in addition to a current setting of 10A and
CV foldback. Note that the power supply output would not
change while the three preset states were being stored because
the output was turned off. The store/recall designators need
not be assigned in consecutive order, but they must be in the
range of 0 to 15.
OUT OFF
VSET SV; ISET 2A: FOLD CC; STO 0
VSET 8V; STO 1
ISET lOA; FOLD CV; STO 2
3-161
Status Register. The power supply maintains a 9
bit status register that reflects the present state of the unit. Each
of the nine bits represents a separate condition; when the con¬
dition is true the corresponding bit is 1. Bits are assigned as
shown in Table 3-9.
3-162
The status register can be read by sending:
STS?
and addressing the power supply to talk. The response from
the power supply is in this format:
STS
XXX
where xxx is a string of ASCII decimal digits. These digits
specify an integer which is equal to the sum of the bit weights
of the true conditions.
3-163
For example, if bits for both ERR (1281 and CC (2)
are set, the power supply would send ASCII digits 1 3 0 (128
+ 2 == 130).
3-164
Bits remain set in the status register as long as the
corresponding conditions are true.
Table 3-9. Status Register
Bit Position
8
6
4
Bit Weight
256
128
64
32
16
Condition
Rl
ERR FOLD AC OT OV OR CC CV
CV
Constant Voltage Mode
CC
Constant Current Mode
OR
Overage
OV
Overvoltage Protection Circuit Tripped
Ot
Overtemperature Protection Circuit
Tripped
AC
AC Line Dropout or Out of Range
FOLD
Foldback Protection Circuit Tripped
ERR
Remote Programming Error
Ri
Remote Inhibit (INH)
3-1^
Accumulated Status Register. Reading the status
register provides the controller only the state of the power sup¬
ply at the time STS? was received. A condition that lasts only
momentarily may not be observed even with frequent polling
of the status register. To ensure that a temporary change can
be noted by the controller, the power supply maintains an ac¬
cumulated status (astatus) register. Table 3-3 describes the
astatus register as well as the status register. A bit in the astatus
register will be 1 if the corresponding bit in the status register
has been 1 at any time since the astatus register was last read.
3-166
The astatus register can be read by sending:
ASTS?
and addressing the power supply to talk. The response from
the power supply is in this format:
ASTS xxx
where xxx is decoded the same way as in the status register
readback.
3-167
The astatus register is reset to the present value of
the status register immediately after it is read by the ASTS?
query.
3-168
Mask and Fault Registers. The power supply has
two additional registers, the mask register and the fault register,
both of which are arranged like the status register (Table 3-9).
3-22
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