LOGGING ENCODER MODULE (LEM)

17.2 LEM SETUP PROCEDURE

17.2.1 LEM SWITCH SETTINGS

See Figure 17-2for Alignment Points Diagram.

Table 17-1 LEM SWITCH SETTINGS

Switch

Open Sections

 

Close Sections

 

 

 

 

 

 

 

 

 

 

S1

1

2

-

4

-

-

3

-

S3

1

2

3

4

-

-

-

-

S4

1

2

3

4

-

-

-

-

S5

-

-

-

-

1

2

3

4

17.2.2 LEM JUMPER PLACEMENT

Table 17-2 LEM JUMPER PLACEMENT

JU

Pin

Description

 

 

 

J24

1 to 2*

Selects 27512 EPROM operation

 

2 to 3

Selects 27256 EPROM operation

J27

1 to 2

Not used

 

2 to 3*

Normal operation

P33

1 to 2

open

 

3 to 4

open

 

5 and 6

open

J36

1 only

Not used

 

1 to 2

-48V E-lead operation

 

2 to 3

-15V E-lead operation

J14

Jumper pin

1 to 2 for high impedance ground path

J15

for split 600 ohm inputs and outputs. Leave open

J21

if no ground path desired.

J22

 

 

* Indicates normal operation.

17.2.3LEM BACKPLANE EXTERNAL CONTACTS

See the Backplane Section 23 for pinouts on the shelf backplane and wire harness pinouts.

The main transmit audio of the LEM is the only external connection that is required. This connects to the logging recorder.

Table 17-3 LEM EXTERNAL CONNECTIONS

Backplane

 

Wire Harness

P34 to P45

Description

 

J1,3,5,7

 

 

 

 

pin 27

Sec Rx +

pin 1

RxS+

pin 28

Sec Rx -

pin 2

RxS-

pin 29

EA lead

pin 3

EA

pin 30

EB lead

pin 4

EB

pin 31

Pri Rx Audio+

pin 5

RxA+

pin 32

Pri Rx Audio-

pin 6

RxA-

 

 

 

J2,4,6,8

 

 

 

 

pin 59

Sec Tx +

TxS+

pin 1

pin 60

Sec Tx -

TxS-

pin 2

pin 61

MA lead

MA

pin 3

pin 62

MB lead

MB

pin 4

pin 63

Pri Tx Audio+

TxA+

pin 5

pin 64

Pri Tx Audio-

TxA-

pin 6

17.3 LEM ALIGNMENT SPECIFICATIONS

17.3.1 PRE-ALIGNMENT

The LEM is pre-aligned with the Basic Board Module alignment procedures. Refer to Section 7.3.

17.3.2 LEM ALIGNMENT PROCEDURE

The main transmit audio of the LEM is the only connection to the logging recorder. Good alignment practice should be followed and the module should be adjusted accordingly.

Connections to the LEM are:

1.Direct Connection

2.Leased Lines

3.Microwave Link

4.T1 Channel Bank Interfaces

This ancillary equipment requires certain input and output levels for proper operation. The module should be adjusted accordingly.

17-2