
LOGGING ENCODER MODULE (LEM)
17.2.1 LEM SWITCH SETTINGS
See Figure
Switch | Open Sections |
| Close Sections |
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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
TableJU | Pin | Description |
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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 | |
| 2 to 3 | |
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 |
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* 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.
Backplane |
| Wire Harness | |
P34 to P45 | Description |
| J1,3,5,7 |
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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- |
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| J2,4,6,8 |
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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 |
17.3.1
The LEM is
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.