Advanced Search

That looks OK but unless the low level signal is < 0.8V it cannot work.

That is, this is a hardware/interfacing issue.

The 7C81 inputs are fine with 5V signals but 1.8V is an indeterminate level
for the TTL level signals that the 7C81 expects

Do you have a data sheet for the encoder?


 

When I have time I will write up a "5aBOB for Dummies". My big router will use a 7c81 x 5aBOB.

Hi
Wiring looks ok to me. Please guide for the below points if they can help
a. Should I decrease the input voltage to 3 V. Will that help?
b. Should I decrease the output voltage of the encoder using a divider?
c. Perhaps changing the below values?
setp    hm2_7c81.0.encoder.00.counter-mode 1
setp    hm2_7c81.0.encoder.00.filter 0
setp    hm2_7c81.0.encoder.00.index-invert 0
setp    hm2_7c81.0.encoder.00.index-mask 0
setp    hm2_7c81.0.encoder.00.index-mask-invert 0

A 1.8V low level is not valid for a 5V single ended encoder output
Maximum low level for TTL signals is 0.8V

This may be a wiring error or similar.

As suggested ,have linked pin to my 7c81 input. Its a single phase encoder. I have set the counter mode to 1. But the values are coming between 1.8v and 5v on my meter. The rawcounts are changing to 1 and then 0. Please help as the encoder is not reading any counts and not changing at all.

I was suggesting wiring the encoder directly to the 7C81 pins
on a different 7C81 connector than the BOB.

(with series 100 Ohm resistors for protection from negative voltage spikes)

Thanks for your reply. But the cheap Chinese boards require 24v power supply to energize its inputs. So inputs are all not responding to 5v input of the encoder. Kindly help as how to wire the 5v inputs with 7c81.

You should be able to use single ended encoder pins directly with a 5V encoder.
The 5abobx3d configuration has encoders on all connectors and the 5abobx2
configuration has encoders on both connectors.

For more input protection, I  would add a say 100 ohm series resistor
to the encoder signal lines.
 

Hi, 

Please can you share a bit file where i can use 5v encoder inputs on my bob P7 for my 7c81 board. I donot want to use 24v but 5v as a quad encoder fast inputs. Rest pins are fine for a normal 5axis bob3 pins.

thanks

Okay,I did a dumb haha. I got a little too hung up on pncconf not picking up the 7i73. So I started linuxcnc and ran halcmd show pin | grep 7i73 and they're all there. I'm just going to set my pins in my hal file and it should be good to go

Thanks for the quick response. I ran mesaflash --device 7c81 --addr /dev/spidev0.0 --spi --sserial and seems like it's communicating with the 7i73! I'm still not sure why pncconf isn't showing it? Is there some extra hal configuration that I need to do?

Here's the truncated output from the mesaflash command, just to show it is there
...
SSLBP port 0:
SSLBP Version: 1.43
SSLBP Channels: 2
SSLBP Baud Rate: 2500000
sserial device at channel 1: 7I73 (unit 0x130001F9)
SwRevision = 14
HwRevision = 1
NVBaudRate = 2.5Mb
NVUnitNumber = 0x130001F9
NVWatchDogTimeout = 50ms
.....

mesaflash --device device_name [options] --sserial


mesaflash --help gives more stuff

or you can try

man mesaflash

Hello all! I'm new here on the forum, I've been searching for a day or so now and can't really seem to figure this out. I've been using the machine with a rpi4, with the 7c81 running the 5abobx2 bitfile setup for a little while now and decided to expand with the 7i73. From what I've read, when using pncconf I should see the 7i73 or at least a way to set pins on the smart serial interface, right? So far, it never seems to show up. I have it connected to the 7c81 via a cat6 cable, and I have a power light on the 7i73. I've set the jumpers on the 7i73 to all the default locations (terminated serial, no lcd, no keypad). when using mesaflash to check the config of the 7c81, I can see the smart serial interface. I feel like there's something very simple I'm missing. I hope this isn't a repeat question, I couldn't find it here. I appreciate any help you can offer

  Module: SSerial
  There are 1 of SSerial in configuration
  Version: 0
  Registers: 6
  BaseAddress: 5B00
  ClockFrequency: 100.000 MHz
  Register Stride: 256 bytes
  Instance Stride: 64 bytes

 

Yeah std breakout board, a lot of the generic Chinese one have a 0-10v converter. Mesa also sells something called spinx1 store.mesanet.com/index.php?route=produc...oduct&product_id=205 which could be connected to the 2nd port on the 7i92T.
Glass sensor would require a buffer circuit of sorts I guess, PCW would have the best advice regarding that.

I've been using an original 7i92 for years (the change was to a different FPGA for the T) and had no issues........plus a number of other cards as things grew


This how good the support from Mesa is. Some users have bought clones from AliExpress (I'd recommend the genuine thing) and he's been happy to help those users out. TBH PCW has helped me out when I got bored and tried to build a clone of a 7c81 based on a Spartan6 FPGA dev board. Which does work either via SPI to Raspberry Pi 4/5 or a PC with a parallel port using the EPP protocol.

You may find some forum users very biased towards Mesa, some build machines professionally and only use Mesa, other have converted a mill or a lathe....or many other machines that I have probably missed. But they all swear by Mesa products.
Not that there aren't other options, but it's the best way if you "just wanna make chips".

Unfortunately, the situation is anything but simple… I reinstalled Bookworm, but the command:
`sudo mesaflash --spi --addr /dev/spidev0.0 --device 7c81 --readhmid`

doesn't work:

- open: No such file or directory
- No 7C81 board found

The following works:

`halcmd -kf`

`halcmd: loadrt hostmot2`

`halcmd: loadrt hm2_rpspi`

`halcmd: show all hm2`

However, I don't know how to write a new bitfile. That is, the equivalent of:

`sudo mesaflash --spi --addr /dev/spidev0.0 --device 7c81 --fallback --write bitfile-name`

I tried installing an older version of LinuxCNC – Buster. However, the libraries for installing mesaflash are missing and cannot be installed because the repositories for this version no longer exist.