I am looking at EtherCAT.
I am using embedded Linux.
etherlab and SOEM have been compiled to test that the EtherCAT master functionality is possible.
But I could not find anything about the EtherCAT slave(S/W).
First of all, etherlab had only master function.
SOES also required specific hardware(Lan9252, twrk60).(https://github.com/OpenEtherCATsociety/SOES/tree/master/soes/hal)
I think ethercat slave is also possible if ethercat master is available with ethernet port.
Is EtherCAT slave a physical hardware (device) unconditionally required, unlike the EtherCAT master?
EtherCAT Slave requires physical ESC(EtherCAT Slave Controller).
Related
I'm writing a linux driver for a DS2484 I2C one wire master, and an accompanying one-wire slave driver for a DS28E84 "DeepCover Radiation-Resistant, High-Capacity, 1-Wire Authenticator". The slaves in our system are hot-pluggable but only slave one may be attached to a one-wire master at any time. There are multiple masters in our system, so there could be more than 1 active slave present at a time.
I have written a "search" function in the master driver that successfully detects when a slave has been attached to the system, and that information is getting properly passed to the "wire" driver so the correct slave driver is associated with a slave device when the search function detects that new slave is present.
I'm unclear how to indicate back to the "wire" driver that the unplugged slave is no longer present. It isn't something the slave device can signal by itself because slaves can get unplugged without warning at any time. The master can determine when the slave has been unplugged, but I'm not sure how the master driver signals to the "wire" driver that the slave should be removed.
I've tried adding a check in the "search" function to see if a previously present device is no longer present, and if so clearing the "W1_SLAVE_ACTIVE" bit in the flags for that missing slave. I was hoping that would trigger the w1_slave_detach() function in the "wire" driver, but that didn't work.
By reading through the code for the "wire" driver, I discovered that the "wire" driver does automatically remove a slave when that slave doesn't report present from the master's search function. However, that removal doesn't necessarily happen the first time the slave isn't present in a search. Instead there is a counter that keeps track of how many times the slave didn't report present. The slave has to miss reporting present for more than a certain number of searches before the "wire" driver removes it.
In my case I was able to change my master driver's parameters so that it sets that "time to live" (ttl) parameter to 1 instead of the default value, and that forced the slave's removal the first time it didn't report present during a search.
I want to set up ptp (precision time protocol) now and HSR protocol in future. So I have a STM32H743ZIT6 and a KSZ8463FRL switch.
The switch has 3 port. According to datasheet port 1 and port 2 can be used as TC (Transparent Clock: P2P/E2E) and port 3 can be used as OC (Ordinary Clock: Master/Slave). I'm confused. Which port should connect to my mcu? Which port should be connect to GMC (Grand Master Clock)? My board is slave for another master now but can my board be used as Master too?
I connect port 3 to mcu and port 1 and 2 is free.
I haven't enough information. Please help me or introduce useful references. Thanks.
Ordinary Clock Ports are uplink facing so Port3 should be connected to GM. This this configuration, the MCU board is slave for GM and can be connected to port 1 or 2.
To use the board as Master, the MCU has to be connected to port 3(Port 3 always connects to Master). The CPU can sync to a GPS and act as GM this way.
The 1588v2 support on STM32H743 may be buggy... as per STM32 forums.
I have 2 Raspberry Pi4, running as first one is master and the second one is slave. They are connected via ethernet cable.
A loadcell and HX711 have been wired to the slave
I would like to read the weight data from the master.
GPIO Zero library(https://gpiozero.readthedocs.io/en/stable/recipes_remote_gpio.html)
Has few examples Led, Button etc. as master and slave
I could not find an example for Hx711.
Does any one has experience with GPIO Zero library and Hx711 server, client solution.
Thanks
I have a cluster of master/slave PostgreSQL replication. I am looking for some kind of application that will proxy all the traffic to the master server. In case of fail-over when slave becomes master, I need that software to auto detect the new master. Currently I am using pgpool II, but it has no ability to auto detect which back-end is master. I mean I need to manually change backend1 (slave) to be backend0 (master) in case of master failure.
Please advice.
This requires considerable setup and is described in detail in chapter 8 of the pgpool 2 documentation.
PostgreSql 9.1 has master-slave synchronous replication. Suppose the master is machine A and the slave is machine B.
If the master fails, how does PostgreSQL know when to make the slave the master? What if the slave incorrectly thought the master was down because of a temporary network glitch on the master where the client program could still contact the master though.
And moreover, how would my client program know the slave in the new master and more importantly is ready to accept writes. Does the slave send a message to the client?
Check repmgr, it's one of its jobs is to deal with this issue.
Typically you want to use a promotion-management system like repmgr or patroni. Then you want to use some sort of a high availability proxy (could be pgbouncer or haproxy) to handle the actual abstraction so your applications do not need to know what system is master.
In answer to your question, most of these systems use a heartbeat to determine if there is a problem. Patroni goes out over the etcd heartbeat. Repmgr has its own heartbeat check. With Repmgr you need to write hook scripts to take care of stonith, and so forth.