The DAQ configuration file is processed at the beginning of each run. The configuration file is processed in a fresh interpreter each time. You therefore cannot maintain any state across runs via your configuration file.
To illustrate module creation and configuration, this let's look at a fragment from a configuration file:
Example 5-1. Creating and configuring devices
ph7xxx create tdc -slot 13 -id 0x7186 -sparse false ph7xxx config tdc -readhits true -usellt false -usehlt false
The ph7xxx driver supports the Phillips 7xxx series
CAMAC 16 channel digitizers. The ph7xxx command is the Tcl
command this driver recognizes. The create
subcommand creates a new device instance and names it tdc.
When you create a module any addition command words following the
device name are interpreted as configuration options.
In this case, the module is configured to be in slot 13,
the driver is configured to emit a literal value (
0x7186 prior to data from the device.
The module is also configured to read all channels
The config subcommand allows you to further
configure the options of a device instance. The second line
of the example continues specifying the configuration of the
device named tdc. The configuration parameters
on that line request the driver to read the hit pattern register
-readhits true), to not
enable either the lower level threshold or the upler level threshold
The reference section 3ccusb provides detailed information that describes each supported device and the configuration options it supports.
Configuration files must also specify at least one stack and, if scaler modules are to be read periodically, a second scaler stack. See the stack(3ccusb) command in the reference material for detailed information about how to create and configure stacks.
To continue with the previous example:
Example 5-2. Configuring an event stack
stack create events stack config events -modules [list tdc] -type event -delay 108
Stacks are created and configured exactly like any other module.
In this configuration file fragment, a stack named
events is created. It is configured to
manage the tdc module (
It is configured as the event stack (
by default is triggered by a nim pulse in the IN1
input of the module. The
specifies a delay of 108usec between the trigger input and stack
execution. This capability is provided to allow the digitizers
in the stack time to convert.
Finally here's a configuration file fragment that sets up an LRS 2551 scaler and the scaler stack: