AMETEK DCS-E 3kW Series - Manual (Page 81)

Sorensen DCS-E Series 3kW Supplies Theory of Operation
M362295-01 Rev C 5-11
transistor Q2 through diodes CR13 and/or CR14, turning ON the transistor, and activating the
LED and the monitor signal.
R EMOTE A NALOG P ROGRAMMING I NPUT C IRCUITS
These circuits are used to buffer, scale, and calibrate the remote analog programming signals
before they are input to the voltage and current control circuits. Op amp U10 and its related
components condition the signal to the voltage control circuit. Input to the circuit is through pin 9
of the rear panel J3 connector. Diodes CR26 and CR27 clamp any out-of-range or reverse
polarity inputs. Trimpot R93 is used to null any offset voltage from U10. Trimpot R60 is used to
calibrate the signal. For programming with remote voltage sources, jumper JMP1 is used to
select either 0-5V or 0-10V input scales. For remote programming with 0-1 mA current sources,
resistor R41 generates the required 0-5V signal from the programming source. For remote
programming with 0-5k ohm resistances, the 1 mA current source provide by op amp U13-B
generates the required 0-5V signal. U13-B and its related parts produce a regulated 1 mA
output by maintaining a fixed 2.5V drop across resistor R97 through transistor Q5.
Operation of the current programming input circuit is the same as the voltage circuit, with op
amps U11 and U13-A and their related components performing the required functions.
R EMOTE S ENSE L INE P ROTECTION C IRCUIT
The remote sense line protection circuit shuts down the power supply output in the event that:
• the sense line connections are reversed,
or
• the positive or negative output load lines become disconnected, with the remote sense
lines connected.
The circuits consists of relays K1 (positive sense) and K2 (negative sense) and diodes CR1 and
CR2. When either of the fault conditions occur, current flows through the relay coils and
activates the relay contacts. This connects +15V to the internal shutdown circuit to disable the
output of the supply. Diodes CR1 and CR2 limit the voltage across the relay coils for reverse
polarity conditions.