225 Series User’s Manual
7
118120-001-Rev. A
Where {numeric string} is an ASCII string of the
required number of digits and a decimal point. The
resolution of the programming meter values is five digits.
Since each model power supply has its own output
rating, the programming command will have its own
format. In general, the programming command will be
one of those shown below:
P0.xxxxxK
(For 500V model)
Px.xxxxK
(For 1kV, 3kV and 5kV models)
Pxx.xxxK
(For 10kV, 20kV, 30kV and 50kV
models)
The numeric format will depend upon the unit being
controlled. This numeric format can be packed with
zeroes to fully five digits. Therefore, if a 225-01R (1kV
model) power supply is to be programmed to only 230V,
the command could be P0.23K or P0.2300K. Similarly,
if a 225-20R (20kV model) power supply is to be
programmed to 11,500V the command could be either
P11.500K or P11.5K.
The actual high voltage output will not change to a
newly programmed value after a program command has
been issued until the unit also receives a device trigger
bus command or the “G” command string (see sections
3.3.4 and 3.4.3).
3.4.1.1 PROGRAMMING
THE
OUTPUT
VOLTAGE AS A PERCENTAGE
This command allows the user to set the output voltage
of the power supply to some percent of maximum output
voltage. The syntax is:
“P (numeric string) %K”
Where (numeric string) is an ASCII string of the required
number of digits and a decimal point. The resolution of
the programming and meter values is four digits.
Pxx.xx%K (for zero to maximum rated output voltage for
all supplies)
The actual high voltage output will not change to a
newly programmed value after a program command has
been issued until the unit also receives a device trigger
bus command or the “G” command string (see sections
3.3.4 and 3.4.3).
3.4.2
SETTING THE OUTPUT LIMITS (“L”)
Each unit monitors output voltage and current to detect if
those parameters exceed the user-set thresholds. Each
parameter (voltage and current) is monitored at the rate
of once per second. The user may set threshold limits
that, when exceeded, will invoke the user programmed
shut down and service request responses (see sections
3.4.6 and 3.4.7). The limit commands consist of an “L”,
a numeric string that represents the threshold value and a
final character that distinguishes between the voltage and
current limits. A “K” indicates a kilovolt limit and an
“M” or “U” indicates a milliamp or microamp limit,
respectively. The syntax is:
“L{numeric string}K”
Kilovolt Limit (All models)
“L{numeric
string}M” Milliamp Limit (All models
except 30kV & 50kV))
“L{numeric string}U”
Microamp Limit (Models 225-
30R & 225-50R only)
Where {numeric string} is as described in Table 3.0.
Note: In some cases, the numeric formats for the voltage
and current will be different.
The voltage limit command uses the same numerical
format as the programming command, but starts with an
“L”. Below are some examples:
Lx.xxxxK
L0.6523k limits to 652.3V
Lxx.xxxK
L29.400K limits to 29.4V
The output current limit threshold may also be set. When
this value is exceeded, the unit will respond as previously
programmed by the user. Below are some examples of
the current limit command:
Lxx.xxxxM
L12.000M limits to 12mA
Lx.xxxxM
L1.0500M limits to 1.05mA
Lxxx.xxU
L473.50U limits to 473.5µA (Models
225-30R & 225-50R only)
An actual limit value will not change to a newly
programmed value after a limit command has been issued
until after the unit also receives a device trigger bus
command or the “G” command string (see sections 3.3.4
and 3.4.3)
3.4.3 ENTERING
THE
CURRENT
PROGRAMMING & LIMIT VALUES (“G”)
After executing a programming or limit command, these
new values will not be used immediately.
The user must execute the “G” command, which will
update the old values with the new ones. Therefore, if the
output is presently programmed to 1kV and the user
executes a program command such as “P1.5000K”, the
output will not change to 1.5kV until the “G” command is
executed. The syntax is:
“G” the single ASCII character
When timing is not important, the “G” may be appended
to the programming or limit command as shown below:
Pxx.xxxKG
Lx.xxxxMG
