原网页：Create a simple EtherCAT IO network (Implementation Notes)
PS：文章最后给了一个知网连接，是在ROS下使用Ethercat的相关论文。
1. 硬件设置（例子）
- T61 联想笔记本 (带 Ethernet 卡)
- IO rack: EtherCAT Couper, 8 DI, & 8DO (all Beckhoff)
2. Beckhoff（倍福） EtherCAT 驱动
- 安装ROS的OROCOS toolchain
- 安装Simple Open EtherCAT Master (soem)库
git clone https://github.com/orocos/rtt_soem.git
- 运行catkin_make，编译连接soem
- 将Ethercat设备连接到以太网口。EtherCAT可通过标准以太网工作。直接建立连接，连接应该不能通过交换机，因为典型的以太网耦合器没有IP地址。
（原文：Connect EtherCAT device to ethernet port. EtherCAT works over standard ethernet cable. Make a direct connection, I do not think connections through switches work since EtherCAT couplers do not have IP addresses (typcially)） - 在 soem_core 包中给 slaveinfo 访问socket命令的root访问权限：
sudo setcap cap_net_raw+ep bin/slaveinfo
（可能需要安装这个：）
sudo apt-get install libcap2-bin
- 执行 slaveinfo 模块：
rosrun soem_core slaveinfo <device, typcially eth0>
模块成功执行时，将会打印一张连接到的从机列表。
7.（最新版的soem中可能不需要这一步）soem堆栈有一个BUG，无法识别未知模块的IO大小。 以下补丁修复了该BUG（已提交BUG）。
diff --git a/soem_master/soem_master_component.cpp b/soem_master/soem_master_component.cpp
index e166ad0..dc6b460 100644
--- a/soem_master/soem_master_component.cpp
+++ b/soem_master/soem_master_component.cpp
@@ -79,6 +79,8 @@ bool SoemMasterComponent::configureHook()
// wait for all slaves to reach PRE_OP state
ec_statecheck(0, EC_STATE_PRE_OP, EC_TIMEOUTSTATE);
+ ec_config(FALSE, &m_IOmap);
+
for (int i = 1; i <= ec_slavecount; i++)
{
SoemDriver
@@ -89,6 +91,8 @@ bool SoemMasterComponent::configureHook()
m_drivers.push_back(driver);
log(Info) << "Created driver for " << ec_slave[i].name
<< ", with address " << ec_slave[i].configadr
+ << ", output bits " << ec_slave[i].Obits
+ << ", input bits " << ec_slave[i].Ibits
<< endlog();
//Adding driver's services to master component
this->provides()->addService(driver->provides());
- 在soem_master目录下运行rosmake编译补丁。
- 编辑 test.ops 脚本，启动master并将OROCOS消息映射到ROS主题。
import("soem_beckhoff_drivers")
loadComponent("Master","soem_master::SoemMasterComponent")
Master.displayAvailableDrivers()
# Default nic is eth0, set if different. e.g.
#Master.ifname = "eth1"
# Crawls the network and identifies attached devices. Devices are loaded
# (if a driver exists) and given names "Slave_1***". The *** appear to be
# the module order (at least this is the case for a single rack)
Master.configure()
# Setting the update period (in seconds). This determines the rate at which
# the data is published on the ROS side (setting this value to zero turns
# off updating
Master.setPeriod(0.05)
# This stars the Master "task" running. It will update at the period set
# above
Master.start()
# This command remaps OROCOS topics to ROS topics
stream("Master.Slave_1002.bits", ros.topic("DI"))
stream("Master.Slave_1003.bits", ros.topic("DO"))
- 在 ocl 包中给 deployer-gnulinux 访问socket命令的root访问权限：
sudo setcap cap_net_raw+ep bin/deployer-gnulinux
- 在命令行中 launch the master：
roslaunch soem_master soem_master_test.launch
launch文件会launch orocos，load test.ops脚本。
3. 其他
- 打开OROCOS消息日志：export ORO_LOGLEVEL=5</tt> （见 [The Orocos Component Builder's Manual - Logging]。(http://www.orocos.org/stable/documentation/rtt/v2.x/doc-xml/orocos-components-manual.html#corelib-logging)）
- OROCOS消息和ROS消息的转换（见 rtt_ros_integration_example）例程脚本：stream("Master.Slave_1002.bits", ros.topic("DI_bits"))
译者注：
这有一篇关于ROS下使用Ethercat的文章：ROS下基于Ethercat的串联机器人控制系统
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