BHK-1/2-MG 030916
3-55
3.9.2.2
MASTER-SLAVE SERIES OPERATION (AUTOMATIC TRACKING)
This configuration is characterized by the fact that only the master power supply is programmed
(controlled), while the slave power supply follows the command of the master in a ratio which
may be predetermined by the user. This method is, therefore, often termed automatic tracking.
A master-slave series combination with a single slave is shown in Figure 3-21 configured to
operate in voltage mode, and in Figure 3-22 to operate in current mode. The master can be con-
trolled either remotely—via either the GPIB bus or by analog means—or locally via the keypad.
The slave can only be programmed by analog programming using external resistance (see also
PAR. 3.8.2). The external resistor (R
EXT
) becomes the input resistor of the uncommitted ampli-
fier (slave) which is configured as an inverting amplifier.
3.9.2.2.1 VOLTAGE MODE OPERATION
When the series combination (Figure 3-21) is operating in voltage mode, both units are in volt-
age mode: the master receives voltage programming commands and the slave tracks the output
voltage of the master.
The output voltage of the series combination in voltage mode is given by the equation,
Eo = Eo
M
+ Eo
S
= Eo
M
+ [Eo
M
x (10/R
EXT
) x (E
O
max
S
/10) ]
=
Eo
M
+ [Eo
M
x (E
O
max
S
/R
EXT
)]
(eq1)
where
Eo
M
, Eo
S
are the output voltages of the master and slave unit, respectively, in Volts
E
O
max
S
is the maximum output voltage of the slave unit, in Volts
R
EXT
is the external programming resistor of the slave unit, in K-ohms.
When R
EXT
(K-ohms) = E
O
max
M
(Volts), then Eo = Eo
M
+ Eo
M
x E
O
max
S
/E
O
max
M
, with the
maximum value of E
O
max = E
O
max
M
+ E
O
max
S
.
When R
EXT
(K-ohms) = E
O
max
S
(Volts), then Eo = 2 x Eo
M
, having the maximum value
E
O
max = 2 x E
O
max
M
.
When the value of R
EXT
(in K-ohms) equals E
O
max
M
(in Volts), as the master is programmed,
the slave will automatically follow proportionally, so the when the master is at maximum output
voltage, the slave will also be at its own maximum output voltage. This combination is practical
when connecting different BHK-MG models in series.
The output of the series combination will be double the output voltage of the master if the value
of R
EXT
(in K-ohms) equals E
O
max
S
(in Volts).
When the maximum master and slave output voltages are different, the value of R
EXT
(in K-
ohms) must always be equal to, or greater than E
O
max
M
(in Volts), otherwise the slave supply
will be programmed to a voltage higher than E
O
max
S
, resulting in an overvoltage condition.
The maximum current delivered by the series combination is dictated by the power supply with
the lowest nominal current and correspondingly, the highest nominal output voltage. For the cur-
rent limit to operate properly, set the desired value of current limit (for the series combination) at
the power supply with the highest nominal output voltage; set the current limit of the other power
supply to a larger value (1% larger or more).
Summary of Contents for BHK-MG Series
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Page 18: ...xii BHK MG030916 FIGURE 1 1 BHK MG 40W SERIES PROGRAMMABLE POWER SUPPLY...
Page 26: ...1 8 BHK 1 2 MG OPR 030916 FIGURE 1 3 RA 24 RACK ADAPTER WITH TWO 1 2 RACK BHK MG 40W UNITS...
Page 35: ...BHK 1 2 MG SERIES 030916 2 3 FIGURE 2 2 BHK MG SERIES REAR PANEL CONTROLS AND CONNECTIONS...
Page 100: ...3 54 BHK 1 2 MG 030916 FIGURE 3 20 SERIES AUTOMATIC CONFIGURATION...
Page 113: ...BHK 1 2 MG 030916 3 67 FIGURE 3 25 PARALLEL MASTER SLAVE CURRENT MODE CONFIGURATION...
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