Ttl Ref In Connector; Power In/Out Connector; Control, Ref Out, Osc In, And Sig Out Fiber Optic Connectors; Sig Mon Connector - Ametek 7124 Instruction Manual

Precision lock-in amplifier

Table of Contents

Chapter 4, FRONT AND REAR PANELS

4.4.04 TTL REF IN Connector

4.4.06 CONTROL, REF OUT, OSC IN, and SIG OUT Fiber

Optic Connectors

4-10

output that can be set high or low by the use of the RCU Digital Port menu or via the

computer interfaces. The port is most commonly used for controlling auxiliary

apparatus, such as lamps, shutters and heaters. Pinouts for this connector are given in

appendix B.

This connector is provided to allow TTL-compatible pulses to be used as the

reference input, if the best possible phase accuracy at low external reference

frequencies is required, when it usually gives better results than the REF IN

connector on the front panel.

When the 7124 RCU is line powered, this connector supplies ±15 V at up to 100 mA

and can be used for powering optional remote preamplifiers available from

SIGNAL RECOVERY. When the model 7124/99 option is fitted, it is used to

connect external DC ±24 V power supplies. Pinouts for this connector are given in

appendix B.

When the model 7124/99 option is fitted the push button mounted above this

connector is used to turn on the unit. With suitable supplies connected, press the

button until the LED on the front panel lights, and then release the button. To turn

off the unit when it is DC powered, momentarily disconnect the Power Input Cable.

These four connectors are used to connect the 7124 RCU to the 7124 main console.

CAUTION: These connectors must be fitted with covers whenever the fibers are

not connected, to prevent ingress of dust or dirt. Any such contamination of the

connectors will impair instrument calibration and may prevent satisfactory

operation. Such contamination is not covered under the instrument warranty.

The signal at this connector is that immediately prior to transmission via the analog

fiber optic data link. If this connector is cabled directly to the AUX IN connector on

the front panel of the main console, and controls on the signal menu are set correctly,

then the fiber link is bypassed. This can be a useful aid to diagnosing problems with

the fiber link, although it clearly then defeats the noise isolation provided by the link

and is not calibrated.

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