Lake Shore Model 647 Magnet Power Supply User’s Manual
Setup & Connections
2-5
2.5.6 MPS Analog Current And Voltage Monitoring Connections
The MPS provides amplified and buffered current and voltage monitor output signals at the terminal block on
the back panel. Connect these signals to external meters to indicate output current and voltage. Obtain the
Current Monitor signal through connections to terminals 9 (Im) and 11 (m) with positive output currents
producing a positive monitor voltage of 10 mV/A from Im to m.
Obtain the Voltage Monitor signal through connections to terminals 10 (Vm) and 11 (m) with positive terminal
voltages producing a positive monitor voltage of 10 mV/V from Vm to m.
Table 2-4
Analog Monitoring, Programming, & Remote Sense Connections
TERMINAL LABEL
DEFINITION
9
Im
Output Current Monitor – Voltage output from Im to
GND(M) is ±10 mV/A.
10
Vm
Output voltage monitor – Voltage output from Vm to
GND(M) is ±10 mV/V.
11
m
Monitor and program ground. GND(m).
12
Vp
Not Used.
13
+Vs
Not Used.
14
–Is
Negative voltage supply for programming external
current with a potentiometer
15
Ip
Current programming input voltage. Voltage input from
Ip to GND(m) produces ±100 A/V. Voltage may come
from a voltage source or from the center tap of a
potentiometer connected from -Is to +Is.
16
+Is
Positive voltage supply for programming external
current with a potentiometer.
17
18
–S
+S
Remote voltage sense correction.
Correction for load lead drops of up to 0.5 V per lead.
Figure 2-3
Analog Monitoring , Programming, & Remote Sense Connections
2.5.7 External Current Programming
Remotely program MPS output current by an external voltage or potentiometer. Enable external analog
programming via the rear panel I MODE switch. When the I MODE switch is in the INT I position, external
current mode is disabled. When the I MODE switch is in the EXT I position, the external programming voltage
is summed with the internal programming voltage. Set the internal programming to zero for external
programming only. Apply an external voltage from lp to m of 0 to 1.25 volts or use a 10 K
Ω
potentiometer to
control the output current over the entire range. Make connections to rear panel detachable terminal block
defined in Tables 2-3 and 2-4 and Figures 2-2 and 2-3. The MPS produces 100 A of output current for 1 V at
the current programming input.
NOTE:
MPS protection circuits reduce the effect of open external programming leads. An open external
programming lead forces external programming voltage to approximately 0 volts.
