HEAT EXCHANGERS

HEAT EXCHANGERS AUTONOMOUS MCU

HEAT EXCHANGERS
HEATMODU.JPG, 12 kB

The Control system HEAT EXCHANGER MODULE is located in a plastic case. When first created this module did not do much. It just took readings of things.

Later converted to a bigger plastic case with new board.
Now the module does much more, and is in a bigger case. The microprocessor is labelled "HET". The processor autonomously runs the intire board including communicating with the net. The importance of this module in the net can not be over emphasised. This module can shut down transmitters. If temperatures rise too much, this module will, and has, shut down broadcasting. This module in historical record has proven more reliable than internal transmitter controls. This module with it's humble beginning deserves a lot of praise.

When testing any aspect of the coolant system, turn off automatics.

You may leave automatics on if you instead turn off automatics on the two transmitter modules. There are two modules to turn off if you do it this way. But the plus is that you will have speech to inform you what you are doing.

When setting limits, turn off automatics while making changes.

This module will spontaneously talk to the net! If you do not disable automatics, the result can be off air time.

Sensor

VISUAL OUTPUT TEMPERATURE

All of the temperature sensors are LM34 chips pressed firmly against the copper and insulated.

Sensor

AURAL OUTPUT TEMPERATURE

Sensor

VISUAL KLYSTRON TEMPERATURE

This sensor is directly on the klystron output. Its placement offers the highest possible speed (reaction time).

Sensor

AURAL KLYSTRON TEMPERATURE

This sensor is directly on the klystron output. Its placement offers the highest possible speed (reaction time).

Sensor

COOLANT LEVEL

John Todd came up with this sensor.
John is an unbelievable magician and comes up with the neatest and simplest sensors...
This sensor is so simple: it is just a black thing that is put in a liquid. It is a black circular float which is also a magnet. There is a reed switch in the center shaft. The white tubing protects the wires that connect to the reed switch. One simply sinks the sensor in liquid to the desired depth. When the level dips too low and uncovers the black float, the heat exchanger module sees the contact opening of the reed switch. The heat exchanger module then communicates this information to the community net. Each transmitter module (visual and aural) are listening. The visual and aural modules (if in automatic mode) shut down the transmitters.

One can test the sensor by DISABLING AUTOMATICS. Then lift the sensor up a ways out of the coolant, and listen for the overhead speakers to announce that the coolant level is low. (Do not disable speech)

John's little sensor really works, and in 2006 saved the day and a lot of money.

For many days prior to the incident a coolant pump was dripping liquid at the shaft. The drip was not bad: only four drops per minute. The dripping appeared to be stable and it seemed the pump would last to a maintenance period (The weekend).

Unfortunately, that was to drastically change. I received a phone call from master control. I was informed that both transmitters were off the air. The operator was accustomed to bringing the transmitter back on air with a simple reset. But now, the operator was telling me that the computer was throwing a warning sign up. The sign stated that this operation was not recommended. When I asked what the caution said, the operator told me "COOLANT LEVEL LOW". When I arrived at the site, I seen a massive wet area spread out on the cement. The situation looked really bad. The intire system was bone dry! All of the coolant was gone. But the transmitters were safe...

Temperature sensing is done with LM34 sensors. Sensors are simple placed against the copper with thermal past. A rail to rail preamp is mounted on a small pc board. All temperature sensors associated with the heat exchanger are monitored by the HEAT EXCHANGER MODULE.

TEMPERATURE SENSORS

Setting internal limits...

Although the PIC MCUs are autonomous, the internal limits can be set remotely from computers.
On the screen one simply moves sliders up and down, two limits above and two limits below the actual parameter. There are too many parameters to be displayed on only one screen. The process takes two screens.
Once the limits are established inside the MCU, the computers can be turned off: my system does not need computers.
When adjusting limits, automatics should be turned off. The limits for the HeatExchanger MCU are especially important: they can shut down transmitters. Also, the coolant level of HeatExchanger MCU can shut down the transmitters. Make shure that automatics are disabled if changes are in the process of being made.

PROGRESSIVE WAKEUP:
It is ok to unplug and plug an MCU unit into the net. All modules boot up with automatics disabled. Also when a unit is initially powered up, the time is set to 99 Minutes and 00 seconds (An absurd value).

"Never startle a proficient gunfighter by waking him from a sound sleep."
-Epitaph

No two way communication can be made untill the time is non absurd. This initial halt of internal action, and halt of communication, gives the unit time to inspect it's enviroment, and establish real, current, and valid readings.
I coined the term "progressive wakeup".