Lakeshore Learning Materials 647 User Manual

Page 56

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Lake Shore Model 647 Magnet Power Supply User’s Manual

Troubleshooting

5-6

14. Set output current to +100 Amps. The DVM

should read about +66 mV. After about 1
minute, the DVM should read +66.666 mV
±0.233 mV (not including offset from Step 9).

15. Set output current to -50 Amps. The DVM

should read about -33 mV. After about 1 minute,

the DVM should read -33.333 mV ±0.117 mV

(not including the offset from Step 9).

16. Set output current to -100 A mps. The DVM

should read about -66 mV. After 1 minute, the

DVM should read -66.666 mV ±0.233 mV (not

including the offset from Step 9).

17. Set output current to 0 A.

Fault/RI Operation Verification

18. Short the MPS RI input with a shorting jumper.

MPS output current should drop to 0 A, and the

alarm should sound about once per second.

Verify the MPS displays the RI screen shown in

Paragraph 3.7.1.

19. With the unit ON, disconnect AC power

connector. The front panel circuit breaker should

trip.

20. The performance verification is complete.

5.5 REAR PANEL CONNECTOR DETAILS


Figure 5-1 MPS Rear Panel Connectors

Table 5-1 Rear Panel Connector Definitions

TERMINAL LABEL

DEFINITION

1
2

RI+
RI–

Remote Inhibit – Active low, TTL-compatible input to remotely
disable the output (force the output settings to 0 A and 1 V).

3
4

FLT +

FLT–

Fault Indicator – Normally open contact closure to indicate a
fault condition has occurred. Contact rating: 0.25 A resistive at
100 VDC, 3 W, 25 VA.

5
6

ON+
ON–

ON Indicator – Contact closure to indicate when the front panel
circuit breaker is in the ON position. Contact rating: 0.25 A
resistive at 100 VDC, 3 W, 25 VA.

7 Reserved

None

8 OVP

Overvoltage Protection Enable – Analog signal connected in
parallel to other MPS Units to remotely activate the output
overvoltage protection circuit.

9 Im

Output Current Monitor – Voltage output from Im to GND(M) is
±0.01 V/A.

10 Vm

Output voltage monitor – Voltage output from Vm to GND(M) is
±0.01 V/V.

11 m

Monitor and program ground. GND(M).

12 Vp

Factory Use Only

13 +Vs

Factory Use Only

14 –Is

Enable external output current programming via MODE switch.

15 Ip

Voltage input from Ip to GND(M) is ±0.01 V/A.

16 +Is

A 10 k

potentiometer from +Is to –Is with center tap to Ip

produces the minimum voltage for full scale current output
(±1.25 V for Model 622 or ±1.55 V for Model 623). Voltage
applied to Ip sums with internal current programming voltage.

17
18

–S
+S

Remote voltage sense correction. Correction for load lead drops
of up to 0.5 V per lead.

Figure 5-2 Serial

Interface Connector

Table 5-2 Serial Interface

Connector Definition

PIN

RS-232C

FUNCTION

RS-485

FUNCTION

1

No

Function

No

Connection

2

Receive

Data

A

3

Signal

Ground

No

Connection

4

Signal

Ground

No

Connection

5

Transmit

Data

B

6

No

Connection

No

Connection

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