Wago Programmable Logic Controllers¶
Wago PLCs¶
Wago PLCs (aka wagoboxes) are composed by:
- an Ethernet communication module. The new ethernet communication module 750-8001 needs an extra entry main_module in the yml config file.
- additional modules containing Input or Output channels for various signals:
- Digital
- Voltage
- Current
- Temperature
- SSI encoder
The Wago class accesses these values by reading or writing specific
modbus registers. The user is allowed to map these input/output channels with
string names through the yaml config file as described after.
TL;DR
Configure the wago in BEACON:
name: wcid42a
plugin: bliss
description: ID42 wago nanoDCM
module: wago.wago
class: Wago
main_module: 750-8001 # only for the new ethernet communication module
tango:
url: tango://id42/wcid42a/tg
modbustcp:
url: wcid42a
mapping:
- type: 750-478
logical_names: ai1, ai2
- type: 750-461
logical_names: pt1, pt2
- type: 750-469
logical_names: tc1, tc2
counter_names: ai1, ai2, pt1, pt2, tc1, tc2
Declare a tango device id42/wcid42a/tg with following resources:
Wago/wcid42a/DEVICE/Modbus: "id42/wcid42a/wcid42a-modbus"
id42/wcid42a/wcid42a-modbus->iphost: wcid42a
id42/wcid42a/wcid42a-modbus->Protocol: TCP
id42/wcid42a/wcid42a-modbus->TCPTimeout: 1000
Wago/wcid42a/DEVICE/Wago: "id42/wcid42a/tg"
id42/wcid42a/tg->beacon_name: wcid42a
Declare interlocks with the following resources:
interlocks:
- relay: relay011
flags: inverted
description: temperature wceudev01
channels:
- logical_name: ai011
type: TC
min: 0
max: 5
- relay: do012
flags: inverted
description: Analog input interlock
channels:
- logical_name: th012
type: TC
min: 20
max: 30
- relay: relay012
flags: inverted
description: monitor test
channels:
- logical_name: th011
type: TC
min: -201
max: 850
flags: MONITOR
dac: dac1
dac_scale: 2.2
dac_offset: 30
The MONITOR flag allows: val(dac1) = dac_scale*val(th11) + dac_offset Remark: dac mnemonic has to be dacxx like dac1.
Create a supervisor start-up script for the server:
[program:Wago_wcid42a]
command=bash -c "source /users/blissadm/conda/miniconda/bin/activate bliss && exec Wago wcid42a"
environment=TANGO_HOST="id42:20000",BEACON_HOST="id42:25000",ORBendPoint="giop:tcp:lid421:"
user=blissadm
startsecs=2
autostart=true
redirect_stderr=true
stdout_logfile=/var/log/%(program_name)s.log
stdout_logfile_maxbytes=1MB
stdout_logfile_backups=10
stdout_capture_maxbytes=1MB
If a single counter is wanted in a session, use: ALIASES.add("tempCryo", wcid42atc1)
Communication with Wago PLCs¶
The communication is implemented through the standard Modbus/TCP protocol.
Modbus Protocol¶
The standard Modbus serial protocol defines mainly:
- 4 memory areas on the device that can be accessed writing, reading or both
- how to construct and send requests to the device and how to interpret responses
What the protocol does not define are information contained in those specific memory areas as this is device dependent.
In order to obtain this information, it is necessary to consult the documentation provided by the producer.
The Modbus/TCP protocol is built on top of the Modbus serial protocol as it encapsulates Modbus messages through a TCP/IP socket usually on standard port 502.
Configuration¶
The configuration is a matter of defining the following:
- Provide connection informations
- Map PLC input/output plugged modules
- Assign some meaningful logical names to input/output
- Define counters
- Define counters gains
- If interlocks are present, provide the configuration
Connection informations¶
Connection to Wago can be done in two ways:
- direct connection
- through Tango Device Server
Note
To use a wago trough a Tango device server requires to configure it and allows to use Tango tools (Jive, AtkPanel, HDB++) to monitor signals.
The connection can be direct with the following configuration:
modbustcp:
url: host:port
modbustcp:
url: wcid42a
Note
If not specified, the default Modbus port 502 is taken.
Or the connection can be done via Tango Device Server using its Fully Qualified Domain Name (FQDN).
tango:
url: tango://[host:port/]domain/family/member
tango:
url: tango://lid42ctrl1:20000/ID42/wcid42a/tg
Note
host:port can be omitted if the global variable TANGO_HOST is defined.
Mapping PLC input/output plugged modules¶
Here is given a basic example of yaml configuration:
name: wcid31l
plugin: bliss
description: ID31 EH I/O Station
module: wago.wago
class: Wago
modbustcp:
url: wcid31l
Basic information have the purpose to identify the device, the kind of device and the host address to allow communications.
As the PLC can be composed following user needs we have to specify what modules are
attached to the Main CPU, this is done using the type keyword. Than we want to
give a name to single input/output and this is done using the logical_names keyword.
If the input/output module has, for example, 4 inputs, we can’t give more than 4 logical_names,
but we can use the same name twice or more to logically group them. In this case we can still
distinguish them later accessing to the logical_channel.
Let’s take this example:
name: wcid31l
plugin: bliss
description: ID31 EH I/O Station
module: wago.wago
class: Wago
modbustcp:
url:wcid31l
mapping:
- type: 750-476
logical_names: pot1vol, pot1cur
- type: 750-530
logical_names: p9,p10,p11,p12,p13,pso,wcdm2c7,wcdm2c8
- type: 750-478
logical_names: pot1out, adc8
- type: 750-478
logical_names: pot2out, adc10
- type: 750-562
logical_names: dac5, dac6
- type: 750-562-UP
logical_names: pot1in, dac8
- type: 750-469
logical_names: th_mask, _
- type: 750-516
logical_names: i0_g,i0_g,i0_g,_
- type: 750-467
logical_names: i0,_
ignore_missing: True
counter_names: pot1vol, pot1cur, pot2vol, pot2cur, i0
counter_gain_names: i0_g
We can see that i0_g is used three times and so we are mapping three
input/output with the same logical_name and they will have a logical_channel
with a progressive number starting from zero. So the first i0_g will have
logical_channel 0, the second will have 1 and so on.
First, the type of board has to be declared then the logical names that will be used to access those channels can be mapped.
Some other examples:
-
Card type 750-476 is a 2 Channel +-10V Input, so 2 logical names, from which float values are expected, will be declared.
-
Card type 750-530 is an 8 Channel Digital Output -> 8 logical names that provide boolean data.
-
The last Card type shows how to behave in the case that there is nothing attached to a channel: an underscore can be used to map it.
The key counter_names has to be organized as a comma separated list of logical
names. These names should be already defined in the preceding mapping.
The key counter_gain_names associates a counter with gains when the hardware
requires it (e.g. novelec electrometer with 3 different gains).
Ignore not mapped channels¶
The additional key ignore_missing is used to avoid exception if a channel is
not mapped on logical_names. Be aware that we can avoid defining last channels
on the module, but we can’t skip.
For example we can go from this:
mapping:
- type: 750-530
logical_names: p9,p10,p11,p12,p13,pso,wcdm2c7,wcdm2c8
ignore_missing: True
mapping:
- type: 750-530
logical_names: p9,p10,p11,p12
Using _ underscore to map unused channels is a convention but is not ignoring
them, simply mapping with the name _.
Simulation¶
We can simulate any Wago simply installing requirements-dev-conda and adding the following entry to the configuration:
simulate: True
The flag simulate: True musst be removed to connect to the real Hardware.
Basic usage from the shell¶
Normally only set and get methods will be needed.
BLISS [1]: w = config.get("transfocator_simulator")
BLISS [2]:
BLISS [2]:
BLISS [2]: wago_simulator = config.get("wago_simulator")
BLISS [3]: wago_simulator
logical logical module module
device channel type description
---------------- --------- -------- --------------------------------------
foh2ctrl 0 750-504 4 Channel Digital Output
foh2ctrl 1 750-504 4 Channel Digital Output
foh2ctrl 2 750-504 4 Channel Digital Output
foh2ctrl 3 750-504 4 Channel Digital Output
foh2pos 0 750-408 4 Channel Digital Input
foh2pos 1 750-408 4 Channel Digital Input
foh2pos 2 750-408 4 Channel Digital Input
foh2pos 3 750-408 4 Channel Digital Input
sain2 0 750-408 4 Channel Digital Input
sain4 0 750-408 4 Channel Digital Input
sain6 0 750-408 4 Channel Digital Input
sain8 0 750-408 4 Channel Digital Input
pres 0 750-408 4 Channel Digital Input
esTf1 0 750-469 2 Channel Ktype Thermocouple Input
esTf2 0 750-469 2 Channel Ktype Thermocouple Input
esTf3 0 750-469 2 Channel Ktype Thermocouple Input
esTf4 0 750-469 2 Channel Ktype Thermocouple Input
esTr1 0 750-469 2 Channel Ktype Thermocouple Input
esTr2 0 750-469 2 Channel Ktype Thermocouple Input
esTr3 0 750-469 2 Channel Ktype Thermocouple Input
esTr4 0 750-469 2 Channel Ktype Thermocouple Input
intlckf1 0 750-517 2 Changeover Relay Output
intlckf2 0 750-517 2 Changeover Relay Output
encoder1 0 750-630 24 bit SSI encoder
special_out_1 0 750-508 2 Channel Digital Output
special_out_2 0 750-508 2 Channel Digital Output
o10v1 0 750-554 2 Channel 4/20mA Output
o10v2 0 750-554 2 Channel 4/20mA Output
double_out 0 750-517 2 Changeover Relay Output
double_out 1 750-517 2 Changeover Relay Output
OK: Given mapping does match Wago attached modules.
BLISS [4]: wago_simulator.get("foh2ctrl")
Out [4]: [1, 0, 1, 1]
BLISS [5]: wago_simulator.set("foh2ctrl",0,0,0,0)
BLISS [6]: wago_simulator.get("foh2ctrl")
Out [6]: [0, 0, 0, 0]
BLISS [7]: wago_simulator.get("esTr1", "esTr2","o10v1")
Out [7]: [78.8, -203.4, 44404]
BLISS [8]: wago_simulator.set("esTr1", 0)
!!! === RuntimeError: Cannot write: 'esTr1' is not an output === !!!