Teledyne Princeton Instruments PI-MTE, System Manual

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72 PI-MTE System Manual Issue 6
Example
Suppose you needed to build a cable to monitor the line TTL OUT 1. One approach
would be to build a cable assembly as described in the following paragraphs. This
procedure could easily be adapted to other situations.
1. Begin with a 25-pin female type D-sub miniature solder type connector (Radio
Shack P/N: 276-1548B). This connector has 25 solder points open on the back.
2. Refer to Table 6-2 and note that Pin 8 = GND and Pin 9 = TTL OUT 1.
3. Using coaxial cable type RG/58U (6 foot length), strip out the end and solder the
outer sheath to pin 8 (GND) and the inner line to pin 9 (TTL OUT 1). Then apply
shielding to the lines to insulate them.
4. Mount the connector in a Shielded Metalized hood (Radio Shack P/N: 276-1536A).
5. Build up the cable (you can use electrical tape) to where the strain relief clamp
holds.
6. Connect a BNC connector (UG-88 Male BNC connector) to the free end of the
cable following the instructions supplied by Radio Shack on the box (Radio Shack
P/N: 278-103).
7. To use this cable, connect the DB-25 to the TTL IN/OUT connector on the back of
the ST-133.
8. To check the cable, launch WinView/32 and open the TTL Diagnostics dialog
(Hardware Setup
►
Diagnostics).
9. Click the Write radio button.
10. Click the Output Line 1 box.
11. Measure the voltage at the BNC connector with a standard voltmeter. Place the red
lead on the central pin, the black lead on the surrounding shielding.
The voltmeter should measure 0 VDC.
12. Click OK button to drive TTL OUT 1 high.
NOTE:
Once the voltage has been set, it remains until a new
command is sent.
13. Again measure the voltage at the BNC connector. The voltmeter should
m5 V
DC
.
Adding a second length of coaxial cable and another BNC connector would be
straightforward. However, as you increase the number of lines to be monitored, it
becomes more convenient to consider using a multiple conductor shielded cable rather
than individual coaxial cables.