suggestions for enhancements to webcontrol (not 32)

CAI_Support said:
Hi Ross,
 
R12 and R13 both 100K divide the analog input for humidity sensor. If you like to change that by replace R12 to 200K or change R13 to 50K, then they will be 10V full scale.  Please note once change made to those resistors, humidity sensor will no longer provide meaningful result.
 
You will need to add protection for analog input, since microprocessor's analog input does not take much current.
 
Thanks, that's fine.
 
I don't like to modify the boards unless its absolutely necessary. NOT changing the boards means that I can swap them out to either faultfind, or to send them away for upgrade or whatever. Also, external solutions make for generic designs others can use.
 
My current thinking is that your 2:1 divider is fine now that I know what's there. If I drive it from an opamp, via a small resistor lets say 1K, and a 6.8V zener to ground on the terminal board, it should clamp the input to the chip itself at 3.4V which should be safe.
 
The advantage with this is other people can use the WebAmp board too, without needing to modify THEIR webcontrol boards (and no potential warranty problems with modified boards).
 
Now I just need to think if I'm better using two webcontrol boards and some inter-board communications, or making a multiplexer on the analog input. I am not sure there are too many people will need 8 A/D inputs, so that may make that board "too specific".
 
If you simply add a 110K resistor in series to the analog input, that will make the humidity range to 10V.  That will have no need for modify the board. You still need to add protection, if your analog input could go beyond 10V before the added resistor.  Please note inside the microprocessor, all the analog inputs share one actual ADC. If this input was overvoltage and caused damage, then all analog inputs will no longer work.
 
CAI_Support said:
If you simply add a 110K resistor in series to the analog input, that will make the humidity range to 10V.  That will have no need for modify the board. You still need to add protection, if your analog input could go beyond 10V before the added resistor.  Please note inside the microprocessor, all the analog inputs share one actual ADC. If this input was overvoltage and caused damage, then all analog inputs will no longer work.
 
OK, we're getting somewhere here.
If I used the same quad-opamp (LM2902), and the same supply (lets say 12V), the maximum output of the opamp will be about 10.7V
Lets assume an input of 13.8V, means opamp output could reach 12.5V
With 110K + 100K = 210K to the chip, and a supply of 3.3V = a V(diff) = 9.2V, across 210K = 0.044mA = 44 microamps.
What is the absolute maximum input current the protection diodes on the inputs can withstand?
I guess my calculations are in error there, 3.3V Vdd, plus 0.6V protection diode = 3.9V from 12.5V = 8.6V / 210K = 41uA.
If the protection diodes can handle that safely then I likely don't need to do anything beyond including the 110K resistor :)
 
WebControl ADC input is capacitive, does not actually take any current other than charging up the capacitor inside chip. 3.3V is labeled by chip manufacture as maximum input. However, we tested with 3.4V without problem.  All the current you calculated is just for current going through the resistor divider. Of course, the lower the resistors value, the better the ADC accuracy, because capacitor got charge up faster inside the chip.
 
WebControl current release firmware is a solid release.  It will be used for all shipment for foreseeable future.
 
To add pulse width measurement will need to remove DS2450 support, if this measurement feature is ever done, it will be an option release for user to pick.  Right now, we are waiting chip manufacture to confirm that is still doable with this chip with our existing features.
 
Agree with everyone else that the current connection method is a PITA.  What I would love to see in a future design is an option with a 50-pin AMP connector so we could use ready-made cables to a 66 block and punch everything down (or for those who don't do punchdown, a fanout cable to a screw terminal block)
 
Also, the ability to have more than 1 counter would be very useful (mabye you could have two counters if you lose the humidity sensor, or something similar)
 
 
 
Do you mean the outputs on the AMP connector also?  AMP connector will add to the manufacture cost. Would have an optional cable allowing punch down acceptable?
 
I see a lot of break out boards using i2C, 1-wire ADC is dead.
Also an ftp-upload of the measured data would be fine, or storing it on board using an SD-card.
 
Efried said:
I see a lot of break out boards using i2C, 1-wire ADC is dead.
Also an ftp-upload of the measured data would be fine, or storing it on board using an SD-card.
 
Thanks so much for your suggestion. It is probably easier to use analog mux than I2C with current firmware.  For this 8 bit board, if we added any new feature, we would have to remove existing feature. We think if we remove anything first, that might be the 1-wire ADC.  Current firmware is solid with existing features.  It is a great board for controlling and monitoring few things, or gang together more than one board through WEBSET feature over the network.  In the future, we might release different firmware, so that user could order board loaded with different firmware for different purpose.
 
There is really no code space to add SD-card or USB support on this 8 bit board.  We do support that on the more expensive 32bit board with limited USB support.
 
We plan to work on adding certain function so that it can be used as EV car 240V charge controller. However, we need to remove certain functions to free some resources. 
 
Current shipping 3.02.17D firmware is stable and will be supplied for normal orders.
 
Functions and features we propose to remove will be 1-wire analog support, out of four allowed host IP address, we will only leave one allowed host.  Please let us know if you have any objection on this.
 
CAI_Support said:
Current shipping 3.02.17D firmware is stable and will be supplied for normal orders.
 
Functions and features we propose to remove will be 1-wire analog support, out of four allowed host IP address, we will only leave one allowed host.  Please let us know if you have any objection on this.
Sorry, a little unclear with the last line. If the above changes are made to the board will that board then be a special order board while the normal order board will still have the 1-wire analog or will that function no longer be available period?
 
Thanks,
Tim
 
Hi Tim,
 

We will probably let purchasers making decision on that.  I would think we will continue ship 3.02.17D firmware by default.
We still work on the firmware. The main function to add  is a PWM output controlled by PLC for frequency and duty cycle, start and stop. Because EV charger needs to change duty cycle to let EV car know charger's max charging amperage. All other logic can be handled in PLC program.
 
Of course, once that is done, users can use PWM output to control other things.
 
Thanks for your feedback. Please let us know what do you think.
 
Just adding some actual developments in my application. First of all I'm missing structured programming possibilities using comments, switches  and true if-then-else blocks.
Secondly wireless connectivity would be great, especially when feeding the board from solar power avoiding cables ZigBee would do or WLAN with new power management .
Last but not least for HVAC applications going into the direction of fuzzy control might be good, also allowing inputs from other web servers using an XML-parser. I understand that that would require 32 bit acrhitecture, so 'm loocking forward to new versions ;-).
 
CAI_Support said:
Thanks so much for your suggestion. It is probably easier to use analog mux than I2C with current firmware.  For this 8 bit board, if we added any new feature, we would have to remove existing feature. We think if we remove anything first, that might be the 1-wire ADC.  Current firmware is solid with existing features.  It is a great board for controlling and monitoring few things, or gang together more than one board through WEBSET feature over the network.  In the future, we might release different firmware, so that user could order board loaded with different firmware for different purpose.
 
There is really no code space to add SD-card or USB support on this 8 bit board.  We do support that on the more expensive 32bit board with limited USB support.
yes 1-wire ADC is discontinued with Maxim. Unfortunately 8 bit ADC resolution is not sufficient for a lot of measuring signals or requires amplifiers adding complexity. Hope we soon see some stacks or break out boards populating a webcontrol biotop ;-)
 
Efried said:
Just adding some actual developments in my application. First of all I'm missing structured programming possibilities using comments, switches  and true if-then-else blocks.
Secondly wireless connectivity would be great, especially when feeding the board from solar power avoiding cables ZigBee would do or WLAN with new power management .
Last but not least for HVAC applications going into the direction of fuzzy control might be good, also allowing inputs from other web servers using an XML-parser. I understand that that would require 32 bit acrhitecture, so 'm loocking forward to new versions ;-).
Thanks for the feedback. There is a little wifi device made by TP-LINK TL-WR702N. In that it has a wifi client mode. If you configured WebControl on your network already, simply configure this tiny little device into wifi client mode, select the SSID and enter your security mode and passphase, then connect WebControl to it. Your WebControl will be on the wifi network through that.
 
You can also using a DC-DC converter to get your solar panel's DC output regulated to 5V, directly power that TP-Link wifi client and WebControl. Please make sure voltage is connected correctly, if powered in a wrong direction, WebControl board will be fried immediately.
 
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