New WebControl 8 board tolerates 70C use 5-40VDC supply

[pittom]

so this is only 0V trigger?  i need high trigger for wc32 any suggestions

 

[CAI_Support]

This is 4V trigger relay board, can be used for both WC8 and WC32:
 

http://www.amazon.com/dp/B00GGKLFXO/

 

[pittom]

thanks

 

[CAI_Support]

That item listing saying 24V relay board, but look the relay closely, it says 5V relay. It is actually operate using 5V power instead of 24V.

 

[pittom]

and the review said it was 5v. I will find out when it comes in

 

[klaatu]

Has this switching power supply upgrade raised the maximum current draw for the board at all?  I've never used these little relay boards and don't know anything about them, but I see 15-20mA as the trigger drive current.  If some combination of sensor inputs and plc code should meet the condition for energizing all 8 relays, that would exceed the 100 mA limit given in my manual?  The WebControlPLCUserGuide3-03-19.pdf for this new board also still says "or 100mA for the whole board".    I used 25A SSRs with only 7.5 mA trigger, partially for this reason, but for the wc32 the loads will be light and I would like to use a small relay board like this for space saving. I had even considered putting a current sensor on the webcontrol power input to monitor realtime current draw, and making a safety provision in the plc code to avoid turning on too many relays at once, if it is going to be an issue.

The manual linked on the ebay page for the wc32 is mostly about PLC code, not much about the hardware specs.    WebControl32rev07-hardware.pdf on cainetworks is, well, a little bleak on details.  Nice pictures tho.  It can drive 16 relays, hopefully the whole-board maximum is higher than 100mA?  When I go to cainetworks products/webcontrol, I only see the wc8.  The ebay pic for the wc32 shows rev 7.0, what looks like a normal voltage regulator, and I don't see a cluster of fat caps or the little 470uh coil, so it looks it hasn't had this upgrade yet.  But WC32PLCProgrammingGuide4-02-06.pdf says "WebControl HW rev 7 changed using a switch IC to regulate the power, it can take from 4.5V to 20VDC."

Just trying to get clarification, seems I bought the .18b5 2.2.x wc8 a moment too soon, the ds2450 was already gone, but the manual linked to it on the listing page still said it was there. & I didn't get the switching supply and spi terminals that came along with the next .19 firmware & 2.3.x board

The temp hardening would also be real nice, I can commonly have 45-48C ambient in the summer, outside the enclosure.  Is there another wc32 revision in the pipeline, coming soon?

 

[rossw]

Has this switching power supply upgrade raised the maximum current draw for the board at all?  I've never used these little relay boards and don't know anything about them, but I see 15-20mA as the trigger drive current.  If some combination of sensor inputs and plc code should meet the condition for energizing all 8 relays, that would exceed the 100 mA limit given in my manual?  The WebControlPLCUserGuide3-03-19.pdf for this new board also still says "or 100mA for the whole board".    I used 25A SSRs with only 7.5 mA trigger, partially for this reason, but for the wc32 the loads will be light and I would like to use a small relay board like this for space saving. I had even considered putting a current sensor on the webcontrol power input to monitor realtime current draw, and making a safety provision in the plc code to avoid turning on too many relays at once, if it is going to be an issue.

 
Several things. What is the context of the "100mA maximum" you're referring to?  If that's the maximum the board *WILL DRAW* that's got nothing to do with how much its onboard power supply might be able to supply, so there may be a terminology difference there.
 
The second thing is, I have a number of boards operating 8 relays, and LEDs. For this application, I generally select 12V relay boards. Their inputs are exactly the same and are easily driven by the webcontrol TTL outputs, but rather than powering them from the (already stressed) onboard supply, I power them from the 12V supply *TO* the webcontrol board, not the onboard regulated supply. I've had no problems with any of my boards in this setup.

 

[klaatu]

Hey Ross.  Thanks for the repsonse.  Don't know which side of the dateline you are on, but it's a nice Sunday afternoon here and I hope your day is just as fine.

I have been interpreting that 100mA maximum as the most current the board can source thru the ttl outputs.  That is coming from this statement in the manual "The maximum current that can be sourced or sinked by one of these outputs at a time is 20mA or 100mA for the whole board." under section "2.2 TTL Output Port".  I am driving my fotek SSRs directly from the 8 outputs, their spec says 7.5 mA draw at 12v, and they can trigger from 3-32v.
 

 I power them from the 12V supply *TO* the webcontrol board, not the onboard regulated supply

So maybe I don't understand what you mean by this.  Well, OK, clearly I don't.  If you are powering the relay coils with 12v from the power adapter supplying the board itself, how is that power being switched by the tll outputs, in order to control the relays, and their loads, by PLC?   Or do you mean, you are powering 12v loads, connected to the relay switches, from the 12V supply to the webcontrol board?  I'm not trying to do that, all my present loads are 110vac.  In the new board, at least 10 of them will be 24vac, a few others 110vac, and maybe a couple 12vdc

Do these relay boards have little ssrs on them that allow the use of some other power supply for the coils, other than directly from the wc8 ttl outputs themselves, and the ttl outputs are just switching the little ssrs?

I agree, the little vr on the board is stressed, and that is my concern, to keep tabs on how much current I am demanding from it.  And I am using 9v, not 12v, it's quite hot here and the enclosure doesn't need a significant extra heat source inside it

 

[rossw]

Hey Ross.  Thanks for the repsonse.  Don't know which side of the dateline you are on, but it's a nice Sunday afternoon here and I hope your day is just as fine.
 

I have been interpreting that 100mA maximum as the most current the board can source thru the ttl outputs.  That is coming from this statement in the manual "The maximum current that can be sourced or sinked by one of these outputs at a time is 20mA or 100mA for the whole board." under section "2.2 TTL Output Port".

 
UTC+10 (Australia), so it's now 8am monday here.
 
OK, yes, running at crossed purposes - the TTL outputs do indeed say they can sink or source 20mA/bit, but maximum of 100mA for the whole part.
The relay boards I'm using all had ULN2003 (or equivalent) and their drive requirements are quite modest. Certainly nothing like 12mA each which they would need to be to cause a problem.
 
 
 
 

So maybe I don't understand what you mean by this.  Well, OK, clearly I don't.  If you are powering the relay coils with 12v from the power adapter supplying the board itself, how is that power being switched by the tll outputs, in order to control the relays, and their loads, by PLC?   Or do you mean, you are powering 12v loads, connected to the relay switches, from the 12V supply to the webcontrol board?  I'm not trying to do that, all my present loads are 110vac.  In the new board, at least 10 of them will be 24vac, a few others 110vac, and maybe a couple 12vdc

Do these relay boards have little ssrs on them that allow the use of some other power supply for the coils, other than directly from the wc8 ttl outputs themselves, and the ttl outputs are just switching the little ssrs?

 
Most, if not all, the relay boards I've seen use an NPN transistor (discrete parts) or similar function IC to drive the relay coils. (Not SSR, that's overkill to merely drive a relay)
Few relay coils need more than 100mA to operate, many require much much less. An open-collector driver with an HFE (gain) of even 100 will only require 1mA base current to operate. I have many boards operating outside in enclosures, that operate fans using nothing more than a BC337 transistor with a 4K7 resistor from base to TTL output, and the fan connected from the transistor collector to +12V. It's small, cheap, silent, has no moving parts to wear out, and operates fine. It also takes virtually no current - a few hundred microamps at most - from the TTL output.

 

[klaatu]

well great, that clears that up, thanks.  Like I said "I've never used these little relay boards and don't know anything about them".  I couldn't see in the picture if there was an extra pin to bring in power for the coils, aside from the logic pins.  So if I use a couple of those w/ the wc32, I don't need to keep this 100mA limit in mind, I can give them a dedicated wall wart.  that's just splendid.  and I won't need a big metal alarm box like I have now to hold the SSRs

I was just reading your weatherstation post trying to understand the plc for the I2C, I also have one of the BMP180s.  when I realized that I wasn't going to figure out the method on my own, I bought an analog baro sensor from digikey, but now I don't have the spare four inputs, so it's back to the BMP.  Going thru the posts about I2C/SPI sensors, there are a lot of mixed mesages, it's hard to sort things out

Handling larger numbers (multiregister mul/div) <=  just plain scary
"Would it be possible controlling SPI via the WC32?"  <=  "Possible"? I suspect... (Short answer: "I don't think so (yet)")
I2C slave device support <=  "This is not an example of good code...or anything good for that matter!"
etc...

don't want to derail/hijack Wayne's thread so I'll desist
 

 

[CAI_Support]

I2C and SPI is fully supported both on WC8 and WC32, if you look WC32 IO expansion board user guide, you can see the details on terminals.
New WC8 2.3.8 board also has I2C and SPI terminals.

 

[rossw]

I2C and SPI is fully supported both on WC8 and WC32, if you look WC32 IO expansion board user guide, you can see the details on terminals.

 
Not quite "fully" - we can't have more than one master on the bus.... WC8 I2C code doesn't fully arbitrate (unless you've done that and haven't told me!)

 

[klaatu]

trying to understand the plc for the I2C

more fundamentally, looking at the picture of the terminals in the io board guide, doesn't help me understand the plc to use those terminals.

"Ross published his PLC code to talk to SPI devices on a WC8 board.  If any sensor requires SPI bus, I am sure you could follow Ross' example to talk to the sensor using PLC programming."
"For the SPI/I2C interface, Ross already published how did he do it in PLC on this forum"
"Ross had already published a SPI logic implemented in PLC code. That has posted in this forum."

Three times said in the Sensor List thread, but not one link.  "go dig", so that's what  I was doing.   The historical perspective finds that scary large numbers post first.  I was reading myself from there into the present, not suggesting that there isn't support.  If I thought there wasn't support, I wouldn't be looking for plc examples to use it

 

[CAI_Support]

@klaatu
 
When you talk to a I2C sensor, you send address byte, and register data, then read the result back. I2C communication protocol is basic protocol, but communication sequences are specific for the sensor you choose.
 
If you have a specific sensor, we can help you to do the PLC code.
 
In the past, we have published I2C talk to pressure sensor PLC code, I2C talk to 2 line LCD display example code. 
 
I2C has a read and a write PLC commands. Maybe follow the I2C 2 line LCD example, that is on this site. Then we can discuss more in details there.
 
@Ross,
you are right, we currently only support single master, in another word, ONE WC8/WC32 can not share sensors with another WC8/WC32 on the same I2C bus. If we see the specific needs, we can work on it for you.

 

[klaatu]

"to the additional analog inputs, there are I2C ADC modules on the market, it is not too hard to program them through PLC"

I rather focus on a specific function that I actually need.  Can I use a 4 Channel 16 Bit ADC like the ADS1115?  Think I heard Ross say the wc8 is 10 bit.  A search for that ADC here comes up dry.  Reading on adafruit now looking at the examples