Parameters
All the functionalities and the communication between processes are ensured by a common list of parameters.
The first 26 parameters (A -> Z) will be saved regularly in the log. These values will be recovered when the pHMeter reboots.
| ID | PARAM | NAME | DESCRIPTION |
|---|---|---|---|
| 0 | A | PARAM_TEMP_EXT1 | Temperature of the solution (top) |
| 1 | B | PARAM_TEMP_EXT2 | Temperature of the solution (bottom) |
| 2 | C | PARAM_PH | pH (raw values) |
| 3 | D | PARAM_PH_H | pH in unit of potential of hydrogen |
| 4 | E | PARAM_PH_TARGET | Desired pH |
| 5 | F | PARAM_PID | pH Control |
| 6 | G | PARAM_EC | Electric Conductivity (raw values) |
| 7 | H | PARAM_EC_US | Electric Conductivity in unit of μSiemens/cm |
| 16 | Q | PARAM_NUMBER_ACQ | Number of acquisition of 100 ms that will be taken |
| 17 | R | PARAM_ACTIVE_PROBES | Number of reading values |
| 18 | S | PARAM_BATTERY | Battery voltage (hundredths of volt) |
| 24 | Y | PARAM_ERROR | Error in the system |
| 25 | Z | PARAM_STATUS | Currently active service |
| 26 | AA | PARAM_PH_FACTOR | PH calibration: conversion factor digital -> H |
| 27 | AB | PARAM_PH_NEUTRAL | PH calibration: digital offset value when pHMeter is full of pure water |
| 28 | AC | PARAM_EC_FACTOR | EC calibration: conversion factor digital -> uS |
| 29 | AD | PARAM_EC_NEUTRAL | EC calibration: digital offset value when pHMeter is full of pure water |
| 51 | AZ | PARAM_ENABLED | Enabled services (set by user) |
Other planned parameters
Others variables are consider with aditional modules that you can connect to the pHMeter via RJ12 port.
| ID | PARAM | PARAM NAME | DESCRIPTION |
|---|---|---|---|
| PARAM_PH_STATE | 0: Pause 1 : normal acquisition, 2 : purge of pipes, 4: calibration pH=4, 7: calibration pH=7, 10: calibration pH=10 |
State machine
There are 3 important variables that will manage the state of the pHMeter:
PARAM_ENABLED: the functions that are currently enabled.PARAM_STATUS: the current status of the pHMeter.PARAM_ERROR: if there is any error in one of the processes.
The PARAM_ENABLED AZ will allow to activate or deactivate some function of the pHMeter. It is for example possible to disable EC while keeping all the other functionalities active.
PARAM_ENABLED
PARAM_ENABLED AZ allows to enable or disable some functionalities of the pHMeter. Currently, it can control alkaline/acid food.
| BIT | PARAM_ENABLED | COMMENT |
|---|---|---|
| 0 | FLAG_OUTPUT_1 | Enable/disable alkaline control |
| 1 | FLAG_OUTPUT_2 | Enable/disable acid control |
| 2 | FLAG_OUTPUT_3 | Enable/disable alkaline/acid aux. control 1 |
| 3 | FLAG_OUTPUT_4 | Enable/disable alkaline/acid aux. control 2 |
If you want to control everything the value of PARAM_ENABLED should be 15.
PARAM_STATUS
PARAM_STATUS Z will display the currently active functionalities. It is composed of different bits that can be enabled or disabled using the method start and stop.
| BIT | PARAM_STATUS | COMMENT |
|---|---|---|
| 0 | FLAG_OUTPUT_1 | Enable/disable alkaline control |
| 1 | FLAG_OUTPUT_2 | Enable/disable acid control |
| 2 | FLAG_OUTPUT_3 | Enable/disable alkaline/acid aux. control |
| 3 | FLAG_OUTPUT_4 | Enable/disable alkaline/acid aux. control |
| 4 | FLAG_EC_READING | Enable/disable EC reading |
| 5 | FLAG_EC_READING | Enable/disable EC calibration |
| 6 | FLAG_PH_CONTROL | Enable/disable pH control |
| 7 | FLAG_PH_CALIBRATE | Enable/disable pH calibration |
| 8 | FLAG_RELAY_ACID | Enable/disable acid addition |
| 9 | FLAG_RELAY_BASE | Enable/disable base addition |
| 10 | FLAG_STATUS_TEST_PROBES | Enable/disable test probes |
The status is currently the Z parameter. You can change the status by changing this value. For example, if you want to force the pHMeter to go in the alkaline state you should ensure that the bits for the outputs, let's say FLAG_OUTPUT_1 & FLAG_PH_CONTROL & FLAG_RELAY_BASE are set. In other words, you may have to add 2^0 (1) + 2^5 (32) + 2^8 (256) = 289 to your value of the parameter Z (in the case it was not yet enabled). Same procedure is to be implemented for acidification and all commands.
The param PARAM_STATUS is the main control when you are running the pHMeter protocol, be sure that those manual changes do not affect your actual test.
PARAM_ERROR
PARAM_ERROR Y will display any error in the pHMeter, you can check the code of the error with this table:
| BIT | PARAM_ERROR | COMMENT |
|---|---|---|
| 0 | FLAG_TEMP_EXT1_PROBE_ERROR | Liquid probe in the top failed (one-wire not answering) |
| 1 | FLAG_TEMP_EXT2_PROBE_ERROR | Liquid probe in the bottom failed (one-wire not answering) |
| 2 | FLAG_TEMP_EXT1_RANGE_ERROR | Temperature of liquid in the top is outside range |
| 3 | FLAG_TEMP_EXT2_RANGE_ERROR | Temperature of liquid in the bottom is outside range |
| 4 | FLAG_PH_RANGE_ERROR | pH is out of range |
| 5 | FLAG_EC_RANGE_ERROR | EC is out of range |
Always have this information at hand, you never know when it can be very helpful.