Lakeshore Learning Materials 622 - Manual (Page 23)

Lake Shore Model 620/622/623/647 Magnet Power Supply User’s Manual
Setup & Connections 2-7
c. Locate Communications Microprocessor (CMP) in the MPS rear panel. The CMP is the module with
two RJ-11 telephone jacks. Loosen two screws securing CMP to MPS rear panel and slide CMP out.
Just inside the CMP front panel, there is a set of DIP switches. Verify that switches 5, 6, and 7 are ON
(closed) and switches 1 through 4 and 8 are OFF (OPEN). (Switches 1–4 define the control bus as
Serial (RS-232C). Switches 5–8 define the control bus as RS-485 multidrop. Switch 8 terminates the
bus for long communications loop runs. Close switch 8 to terminate the control bus only if the MPS
units are a significant distance from each other.) Replace the CMP.
3. Configure the second MPS as MPS 2:
a. Locate the CAL AND ID switches on the rear panel. Turn ON (up position) switches 2 and 4. Turn
OFF (down position) switches 1, 3, and 5 through 8. (Switch 4 ON designates Multiple MPS operation.
Switches 3, 2 and 1 as OFF, ON, OFF, respectively, assign the MPS address as 2.)
b. Move the I MODE switch to the INTernal (up) position.
c. On the CMP, verify that switches 5, 6 and 7 are ON (closed) and switches 1 through 4 and 8 are OFF
(OPEN). Replace the CMP.
4. Connect the control bus. Use Lake Shore Model 2001 Modular Cables (provided) to interconnect the two
MPS CMP units.
5. Connect the MPS 1 over voltage protection (OVP) pin 8 to MPS 2 pin 8.
6. Connect the RI and FLT signals. Connect the +RI (terminal 1) to the +FLT (terminal 3) on MPS 2. Connect
the –RI (terminal 2) to the –FLT (terminal 4) on MPS 2. Do the same on MPS 1. Connect the +RI/+FLT
connection of MPS 2 to the +RI/+FLT connection of MPS 1. Connect the –RI/–FLT connection of MPS 2 to
the –RI/–FLT connection of MPS 1. If an external contact closure will remotely inhibit operation, connect it
across the +RI and –RI terminals of MPS 1. The +FLT and –FLT contact closure of MPS 1 indicates a
fault.
7. Connect the +OUT terminal of MPS 1 to the +OUT terminal of MPS 2. Connect the –OUT terminal of MPS
1 to the –OUT terminal of MPS 2. Make these leads as short as possible to minimize output potential
differences between the two MPS units and large enough to handle the maximum MPS current. Connect
the output terminals to the load using leads large enough to handle the total output current of both MPS
units.
NOTE: For proper operation, turn on MPS 1 and then MPS 2 within 15 seconds of MPS 1.
8. Verify all connections as summarized in Table 2-4.
9. To add a third MPS or a fourth MPS in parallel, make the RI/FLT,
OVP, CMP and output connections in parallel with the
connections of MPS 1 and MPS 2. For MPS 3, set the CAL AND
ID switches on the rear panel as follows : switches 5 through 8
are OFF, switches 4, 3, 2 and 1 are ON, OFF, ON, ON
respectively. For MPS 4, set the rear panel CAL AND ID
switches as follows : switches 5 through 8 are OFF, switches 4,
3, 2 and 1 are ON, ON, OFF, OFF respectively. Configure the
CMP switches for MPS 3 and MPS 4 as those in MPS 1 and
MPS 2.
NOTE: For proper operation, turn on MPS 1 and then the remaining MPS units within 15 seconds.
Table 2-3. Two-MPS Autoparallel
Configuration Connections
MPS 1 MPS 2
Control Bus
8 (OVP)
1 (+RI), 3 (+FLT)
2 (–RI), 4 (–FLT)
+OUT
–OUT Control Bus
8 (OVP)
1 (+RI), 3 (+FLT)
2 (–RI), 4 (–FLT)
+OUT
–OUT