mesa board 7i77 analogue input

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20 Jul 2023 09:25 #275871 by bkt
insert in my hal file these row:

loadrt hm2_pci config=" num_encoders=4 num_pwmgens=0 num_3pwmgens=0 num_stepgens=0 sserial_port_0=200xxxxx "

can read analogue input ... but how wire it? because I try to connect a sensor that send me 0-5V signal .... so can connect GND of sensor to TB2 power field GROUND and connect other signal (+5V) to INPUT0 for example? ... because before wire I would make me certain to not fire some input line. And can grab somethings of intelligent or resolution can be too low?

Regards
bkt

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20 Jul 2023 09:56 #275878 by JPL
Replied by JPL on topic mesa board 7i77 analogue input

 .... so can connect GND of sensor to TB2 power field GROUND and connect other signal (+5V) to INPUT0 for example?
 


Yes, I'm using this and this is how to connect it. But resolution is only 8 bits and accuracy is +-5%. 

Have you seen this on page 17:

ANALOG INPUTS
All field input pins are capable of reading the input voltage. These are not highly
accurate or high resolution but can be useful for things like potentiometer inputs. Input
resolution is 8 bits and input full scale value is 36.3V. Accuracy is +-5%. Software process
data modes 1 and 2 allow reading the analog voltage on inputs 0 through 3, in addition to
the 32 digital bit inputs. 


PCW confirmed to me that this should read data mode 1,2 or 3  (not just data mode 1 or 2). Also I'm really puzzled about where the 36.3v come from. I'm using this to read a pot ( 0 - wiper - field voltage ) and this is good enough for that.
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20 Jul 2023 10:01 #275880 by JPL
Replied by JPL on topic mesa board 7i77 analogue input
Just wanted to add that the 7i87 is much better, if you need better precision and more channels.

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28 Jul 2023 09:10 #276445 by bkt
Replied by bkt on topic mesa board 7i77 analogue input
need to read 0-5V signal at 20mA ..... when can see 0-1-2-3-4-5V signal is enought for me ... no more of these pecision ....

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28 Jul 2023 12:29 #276454 by rodw
Replied by rodw on topic mesa board 7i77 analogue input

need to read 0-5V signal at 20mA ..... when can see 0-1-2-3-4-5V signal is enought for me ... no more of these pecision ....

The mesa analogs are full scale @36 volts. (well the 7i76e is)
I would use a LM358 signal amplifier to step up to 20-22 volts max given a 24v reference voltage. You can get pre built modules from eBay/Amazon/AliExpress for $2 or less.
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31 Jul 2023 04:32 #276601 by bkt
Replied by bkt on topic mesa board 7i77 analogue input
How can set data mode 1,2 or 3?

these row is not enought?

need to set mesa driver?

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31 Jul 2023 05:23 #276606 by JPL
Replied by JPL on topic mesa board 7i77 analogue input
Data mode is set via sserial_port_0=200xxxxx of your row. This is for mode 2.
To set mode 1 simply replace with sserial_port_0=100xxxxx

Once done, for mode 1, 2 or 3, you should be able to find pins name ending with something like 7i77.0.0.analogin0 to 7i77.0.0.analogin3  with 'show  HAL configuration'.


 
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15 Aug 2023 07:54 #278031 by bkt
Replied by bkt on topic mesa board 7i77 analogue input
thanks to all .... solved my problem

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