E907 TPC Electronics Notes

Current Job List
Electrical Description
Sticks
DC Power Supplies and Interlock
Clock and Trigger
Gating Grid
High Voltage in MTest

Electrical Description

Description (html) of the TPC and electrical systems: sticks, DC power, interlocks, receiver cards, high voltage, and grounding. This is the primary reference for the electrical safety review. (Also available as Word and pdf.)

Sticks

Photos
Schematics
Connector pinouts
Stick Serial Number: set by traces, readout.
BitBus Node Number: set by the chamber slot, readout.
DC Power Interlock makeup at the chamber

Stick history (also as Excel oocalc)

Stick Serial Number and BitBus Node Number

The stick Serial number is set by cutting traces around U703 (source):

The Serial and Node numbers are read out by the housekeeping mux, via (source)

Note the pull-up resistors. Cutting the serial number trace sets the bit to "1". Therefore the node address for a stick outside the chamber should consist of all 1's. It appears that Node-6 is always 0 (grounded), and Node-5 is always 1 (+5V), since the BitBus finds nodes in the range 0x20 to 0x3F in each quadrant.

The Node bits 0-3 come from the chamber via the A side analog-digital connector (source):

The node bits 4-6 come from the chamber via the B side analog-digital connector (source):

Chamber Interlock and Node Number

The Interlock -A, -B, and Node bits connections are made at the outboard edges of the chamber (source):

DC Power and Interlock Connector

The DC power and DC interlock come in on a 17 pin Molex connector (source).

The DC interlock passes through an overtemperature switch (shown above), then from one side of the stick to the other on the outboard Bieser pin, and finally back through the A-side to B-side connection to complete the loop. Therefore, to turn on a power supply channel, pins 1 and 17 on the output Molex have to be connected together.

DC Power Supplies

Master Interlock

The Master Interlock requires

• a CLK input, which sensed by rectifying and integrating it;
• a WATER input, which is sensed by sending 24V to an external relay contact.

These can be over-ridden with a jumper on PG13. [This could/should? be converted to an external enable, by putting this connector in series with S3, the front panel panic button.]

Lore has it that the sticks latch up and burn out a chip if the DC power is applied without the CLK.

In addition, each Airflow Interlock, including the Master Interlock, requires

• sufficient airflow to keep the sensor cool.

Power Supplies

To operate, the power supplies receive

• +24V from Airflow Interlock PG9-xA,
• GND from Airflow Interlock PG9-xC,

and, when a channel is on, return

• +24V to Airflow Interlock PG9-xB, which illuminates the lamp on the Airflow Interlock and the Master Interlock.

In order to turn on an individual DC power supply the channel interlock must make up by:

• fully inserting the stick in the chamber,
• jumpering the outboard contacts on the SHAPER boards from the A side to the B side,
• or jumpering pins 1 and 17 on the power supply output Molex connector.

Clock and Trigger

TPC Trigger System and Cable Plant
Clock and Trigger Module

Gating Grid

High Voltage Electrical Systems in MTest

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PDB, 9/19/02