Stereoboard VLPC Temperature Control

Stefan Gruenendahl

Date: 11/13/2023

# 

# 

This note describes certain technical aspects of the VLPC cassette
temperature control system as implemented using Stereoboards in Lab 3.
For a more general description of the VLPC temperature control system,
see the note \'VLPC Temperature Control Hardware\' (August 1998)[^1],
included in the VLPC Cassette Technical Design Report.

# 

# 1.Overview

The system consists of the following components:

1.  Temperature sensor and heater card

2.  Cold end pigtail cin::apse connector

3.  Flex cable

4.  Warm end Cin::apse connector

5.  Stereoboard

6.  J3 connector interface card

7.  Short ribbon cable

8.  T-control distribution board

9.  Long ribbon cable

10. Long heater cables

11. DIN rail terminal

12. Siemens/TI PLC with RTD modules (sensor) and analog output modules
    (heater)

# 2.Details

# 1.Temperature sensor and heater card 

From the hardware note: \"The VLPC system for the DØ central tracker
upgrade will consist of 80 \[May 2000: 102\] cassettes. Each cassette
has 1024 VLPC channels, in 8 modules per cassette, 16 chips à 8 VLPC
pixels per module. Each module has a heater/sensor card (HSC) \[drawing
number 3823.113-MB-317558\] containing one temperature sensor and two
heaters mounted on the bottom of the isotherm \[part number MB-317278\].
Electrical connections to the HSC are made via a flex cable and an
eight-pin cin::apse connector \[drawing number 3823.113-MB-317274\]. All
the modules in a cassette will be thermally coupled, and in standard
operation mode it is intended to use only one temperature sensor per
cassette to control all the heaters in that cassette.

The sensor and heater lines will be routed through the right-hand
front-end electronic boards to the backplane, from were they will be
transmitted through appropriately shielded cables to the control system.
Industrial PID controllers will be used.\"

### 2.Cold end pigtail cin::apse connector

The connector has eight contact pads:

  ---------------- ---------------- ---------------- --------------------
  8                7                6                5

  1                2                3                4
  ---------------- ---------------- ---------------- --------------------

  ---------- ------------------------------------------------------------
  1 and 8:   heater 1

  2 and 7:   heater 2

  3 and 4:   Current source and voltage sense for side A of sensor
             resistor; contact pads 3 and 4 on warm end cin::apse.

  5 and 6:   Current source and voltage sense for side B of sensor
             resistor; contact pads 9 and 10 on warm end cin::apse.
  ---------- ------------------------------------------------------------

### 

### 3.Flex cable

### 4.Warm end Cin::apse connector

### 5.Right hand Stereoboard

The heaters connect to row 1 and 3 of a 3 by 2 jumper panel (J29/J30,
J32/J33,...,J50/J51; see sketch). Resistor 1 connects across pin 1 & 6,
resistor 2 across pin 2 & 5. The modules are chained in two parallel
series of four modules: Pin 4 chains each module to pin 3 of its left
neighbour, or, for modules 1 and 5, to pin A17 of the J3 connector. Pin
3 chains the module to pin 4 of its neighbour to the right or, for
modules 4 and 8, to pin A18 of the J3 connector.

  ----------------------------------- -----------------------------------
  1                                   2

  3                                   4

  5                                   6
  ----------------------------------- -----------------------------------

### Both sensor voltage readback lines connect via 50 Ohm series resistors to the J3 backplane connector (pins A1-A16). 

### One of the current driver lines connects via pin 5 of the obsolete on-board current driver chips RF1 - RF8 to a common bus, and from there (via a wire from pin 5 of RF8) to the J3 backplane connector (C17, C19, C21,..C25, B21, B23, B25). The other of the current driver lines connects via one of eight special wires from the bottom pin of jumpers J31, J34,...,J52 to its corresponding pin on the J3 backplane connector (pins C18,C20,...,C26, B22, B24, B26). 

### On Stereoboards equipped with current driver chips pin 5 of those chips has to be cut. To decouple the other line from the current driver chip, either pin 4 of that chip has to be cut, too, or (preferred solution) the 100 Ohm resistor R100, R102,...,R114 connected to pin 4 has to be removed. On new Stereoboards the chips RF1 to RF8 should not be installed.

On right-hand board number 10 J3 pin A1 is broken, and is bypassed via
B1. A corresponding modification has to be made to all J3 connector
interface cards.

### 

### 6.J3 connector interface card

  ----------------------- ----------------------- -----------------------
  C1                      B1                      A1

  C2                                              

  C3                                              

  ...                                             

  C32                                             
  ----------------------- ----------------------- -----------------------

A1 - A16: Temperature sensor voltage sense. Not ground free, due to
current driver bus (see above).

A17 - A18: Heater double chain. Ground free. Nominally 1250 Ohm cold,
greater than 2000 Ohm when one of the two subchains M1 - M4 or M5 - M8
is broken.

C1 - C16: VLPC bias M1 - M8. Remember that we run positive bias to the
VLPC pixels via the series resistor packs and signal lines. The lines
formerly called \'bias\' connect to analog ground.

C17 - C26: Temperature sensor current driver connections for M1 - M5. On
the Stereoboard every second (even numbered) pin connects to a common
bus line, this connects pin 5 of all on-board current driver chip
locations. (There is no current driver chip on the board, but the
original layout foresaw one per module). On the interface card, all
connections are made to separate wire pairs that run (via the long
ribbon cable) to the Siemens/TI cryo controller.

A/B/C 27-32: cut off, to accommodate PC board support rail.

B21 - B26: Temperature sensor current driver connections for M6 - M8.

### 7.Short ribbon cable

All 16 temperature sensor/driver pairs are brought from the J3 interface
card to the cryostat-mounted Temperature Control Distribution Board.

### 8.T-control distribution board

This board has four slots to plug in the short ribbon cables. Slot 1
corresponds to \'Cassette 1\' of the Siemens/TI cryo control system, and
reads out all eight temperature sensors. Slots 2 to 4 have connections
only to read out module 4.

The heaters for slots 2 to 4 are powered via separate cables, which plug
directly into the distribution board next to the short ribbon cable
connectors. Since the heater connection is ground free on the cassette
side, polarity does not matter.

### 9.Long ribbon cable

The long ribbon cable contains all 11 temperature sensor connections (2
pairs each), plus the heater driver pair for cryo control \'Cassette
1\'. Each pair consists of a coloured and a corresponding brown-beige
wire.

### 10.Long heater cables

There are four separate shielded pair cables with red insulation to
drive the heater chains for the four cassettes. The long heater cable
for cryo control \'Cassette 1\' runs from the back of the cryo control
rack towards the cryostat, but then loops back to the DIN rail, where it
connects to the long ribbon cable. The other three long heater cables
run directly from the back of the cryo control rack to the cryostat.

### 11.DIN rail terminal

The DIN rail terminal has two levels of connections. Cryo control
\'Cassette\' 1 uses the back level and connects to the RTD input module
in slot 9, \'Cassette\' 2 to 4 use the front level, which connects to
the RTD module in slot 15. Within a channel, the wire order is preserved
from the DIN rail to the RTD for the first (slot 9) RTD, but not for the
second (slot 15) RTD.

Each sensor channel has four wires from the long ribbon cable feeding
into the bottom of the rail. For the first RTD (serving cryo
\'Cassette\' 1) the order is, from left to right on the rail, and top
down on the RTD: current positive (I+), voltage sense positive (V+),
voltage sense negative (G), current negative (H). Indicated in brackets
are the markings on the RTD module. The first and second wires are the
brown-beige members of their respective pairs, the last two are
coloured. These wires connect to four intermediate wires at the top of
the rail, which run to the RTD input module: green, red, black, and
white. The heater pair for this cassette runs through rail terminals 33
and 34, the third and fourth from the right.

The front level of the rail connects the three sensors for cryo
\'cassettes\' 2 to 4. Currently (June 2000), only 2 and 3 are hooked up.
For these sensors, the intermediate wire order at the RTD is red (I+),
black (V+), white (G), and green (H). At the rail, the order is green,
red, black, and white. Correspondingly, the long ribbon pairs have to be
connected in a different order, compared to \'Cassette\' 1.

### 

### 12.Siemens/TI Programmable Logic Controller with RTD modules (sensor) and analog output modules (heater) 

The RTD input modules[^2] have 16 input channels each, with two channels
forming a group with common ground. (This channel grouping manifests
itself when a broken connection in one channel leads to wrong
measurement values for its neighbour.) Care has to be taken to depress
the release lever when removing or inserting a wire. Problems observed
thus far were related to insufficient length of the inserted bare wire,
and to shorting of neighbouring wires right at the RTD input.

Mapping into RTD channels:

+-----------------------+------------------------+---------------------+
| Channel               | RTD                    | RTD                 |
|                       |                        |                     |
|                       | slot 9                 | slot 15             |
|                       |                        |                     |
|                       | Cassette/Module        |                     |
+-----------------------+------------------------+---------------------+
| 1                     |                        | C2-M4               |
+-----------------------+------------------------+---------------------+
| 2                     |                        | C3-M4               |
+-----------------------+------------------------+---------------------+
| 3                     |                        | C4-M4               |
+-----------------------+------------------------+---------------------+
| 4                     |                        | spare               |
+-----------------------+------------------------+---------------------+
| 5                     |                        | spare               |
+-----------------------+------------------------+---------------------+
| 6                     |                        |                     |
+-----------------------+------------------------+---------------------+
| 7                     |                        |                     |
+-----------------------+------------------------+---------------------+
| 8                     | C1-M1                  |                     |
+-----------------------+------------------------+---------------------+
| 9                     | C1-M2                  |                     |
+-----------------------+------------------------+---------------------+
| 10                    | C1-M3                  |                     |
+-----------------------+------------------------+---------------------+
| 11                    | C1-M4                  |                     |
+-----------------------+------------------------+---------------------+
| 12                    | C1-M5                  |                     |
+-----------------------+------------------------+---------------------+
| 13                    | C1-M6                  |                     |
+-----------------------+------------------------+---------------------+
| 14                    |                        |                     |
+-----------------------+------------------------+---------------------+
| 15                    | C1-M8                  |                     |
+-----------------------+------------------------+---------------------+
| 16                    | C1-M7                  |                     |
+-----------------------+------------------------+---------------------+

### 

The outputs are routed from the analog modules[^3] through a DIN rail in
the back. The terminals are WY49 and WY61 (in parallel) for \'cassette\'
1, WY50/WY62 for \'cassette\' 2, WY51/WY63 for 3, and WY52/WY64 for 4.
Additional power for the analog modules, to achieve 20 mA through 2 kOhm
per channel, is provided by a Hewlett Packard HP E3630A power supply set
at 23.3 V. The black wire from the COM terminal connects to a short (4
wide) rail on the back level of the DIN rail behind WY49 - WY52. The red
wire from the +20V terminal connects to the bottom terminal of the fuse
holder, to the right of WY64.

### 

### 

### 

[^1]: <http://d0server1.fnal.gov/projects/SciFi/Temperature_Control/tc_master_aug_98.ps>

[^2]: <http://www.aut.sea.siemens.com/505/manuals/q2807060.pdf>

[^3]: <http://www.aut.sea.siemens.com/505/manuals/q2591824d.pdf>