From 100a0f2d82608863338e61ce89cb3854bd48dc6e Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@xfel.eu>
Date: Sat, 6 Apr 2024 18:45:23 +0000
Subject: [PATCH] add examples to documentation
---
ebpfcat/ethercat.rst | 8 ++++++--
examples/ethercat.py | 29 +++++++++++++++++++++++++++++
2 files changed, 35 insertions(+), 2 deletions(-)
create mode 100644 examples/ethercat.py
diff --git a/ebpfcat/ethercat.rst b/ebpfcat/ethercat.rst
index fc4642b..6f83f56 100644
--- a/ebpfcat/ethercat.rst
+++ b/ebpfcat/ethercat.rst
@@ -17,14 +17,14 @@ we need to use await, which can only be done in an async function::
async def main():
master = FastEtherCat("eth0")
await master.connect()
- await master.scan_bus()
+ print('Number of terminals:', await master.count())
asyncio.run(main())
Next we create an object for each terminal that we want to use. As an example,
take some Beckhoff output terminal::
- from ebpfcat.terminals import EL4104, Generic
+ from ebpfcat.terminals import EL4104
out = EL4104(master)
@@ -62,6 +62,10 @@ output a value like so::
ao.value = 5 # set the value on the terminal
+For reference, here is a complete code example:
+
+.. literalinclude:: /examples/ethercat.py
+
Writing a device
----------------
diff --git a/examples/ethercat.py b/examples/ethercat.py
new file mode 100644
index 0000000..45f2415
--- /dev/null
+++ b/examples/ethercat.py
@@ -0,0 +1,29 @@
+"""A simple example of an EtherCat control
+
+this is only an illustrative example to be read. It will not work unless
+you happen to have an EtherCat setup where a Beckhoff EL4101 terminal is
+the second terminal in the line.
+"""
+import asyncio
+from ebpfcat.ebpfcat import FastEtherCat, SyncGroup
+from ebpfcat.devices import AnalogOutput
+from ebpfcat.terminals import EL4104
+
+
+async def main():
+ master = FastEtherCat("eth0")
+ await master.connect()
+ print("Number of terminals:", await master.count())
+ out = EL4104(master)
+ await out.initialize(-2, 20)
+ ao = AnalogOutput(out.ch2_value) # use channel 1 of terminal "out"
+ sg = SyncGroup(master, [ao]) # this sync group only contains one terminal
+ task = sg.start() # start operating the terminals
+ for i in range(10):
+ # we would measure an increasing value on the terminal output
+ ao.value = i
+ await asyncio.sleep(0.1)
+
+ task.cancel() # stop the sync group
+
+asyncio.run(main())
--
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