Hi Jan,

I usually keep under /Experiment/Run Parameters only those settings which are kind of "global" and thus of
interest to frontend *and* analyzer, like a run mode (data/calibration/cosmic/...). Settings more specific to a
frontend I keep under /Equipment/<name>/Settings where <name> is the equipment name the specific frontend
produces. In your case each frontend will then get its own tree (related to each fragment). Please note that
both discussed trees can contain a whole tree with subdirectories, which lets you organize your data better.

Best regards, Stefan.

Hi,

I have a question related to the frontend and I would need some suggestions
about the proper way of doing things in Midas.

I have some CAEN ADC boards and a VME interface and I made a simple frontend
that configures and reads the system and it works great ... Now I would like to
add a feature and it seems to me I am going the wrong way.

I would like to add manual trigger capability and so I added the EQ_MANUAL_TRIG
flag to the "CAEN" equipment type but the problem is that the framework calls
directly the readout function on "Midas manual trigger". To trigger manually the
CAEN ADC's I have to write some registers and therefore I either need to have a
function called before the readout function or be able in the readout function
to know if the call has been triggered by the poll function or "Midas manual
trigger". I tried to check the value *((DWORD *)pevent) but it seems to be a
well defined and meaningful value only when the readout function call is
triggered by the poll function.

So my question is what's the proper "Midas way" of doing this? Should I create a
new equipment which is of EQ_MANUAL_TRIG type and its readout function writes
the registers on the CAEN ADC's to trigger manually the boards? Is there a way
of "mapping" the Midas manual trigger to a "trigger generator function"? Because
I am a little bit confused ... Is the Midas manual trigger on the new equipment
(let's say "Manual trigger manager") going to increment the event ID? Then when
the event is really read through the readout function of the "CAEN" equipment
the event ID is going to be incremented again obviously ... 

Thanks a lot,
Razvan

> I would like to add manual trigger capability and so I added the EQ_MANUAL_TRIG
> flag to the "CAEN" equipment type but the problem is that the framework calls
> directly the readout function on "Midas manual trigger". To trigger manually the
> CAEN ADC's I have to write some registers and therefore I either need to have a
> function called before the readout function or be able in the readout function
> to know if the call has been triggered by the poll function or "Midas manual
> trigger". I tried to check the value *((DWORD *)pevent) but it seems to be a
> well defined and meaningful value only when the readout function call is
> triggered by the poll function.

Actually there is no way to figure out if your readout function is called normally or 
manually triggered. So I modified the framework to add this functionality. In your 
readout routing you can how call

  flag = DATA_SIZE(pevent);

If flag is zero, this is a normal call, if it's one, it's a manual trigger. To get 
this functionality, you have to update midas.h and mfe.c from the repository (rev. 
4519).

Backend computer with SLC4.4 Linux did'not work as mserver because some security
protection under iptables service (could not connect with frontend computers).
The connection established if to make ( under root ) iptables disable
by command: service iptables stop, or much more gently
just to accept mserver port with command (under root):
iptables -I INPUT -p tcp --dport 1175 -j ACCEPT
( in /etc/service 
  midas    1175/tcp       #Midas server)
To check which ports is open
it is possible to use the command: "netstat -n" to see digital numbers of ports.

Hi,
   the system I'm building will have data read into the frontend nodes
via ethernet (optic). Is this possible?>

Fragmented polled events have been implemented in SVN revision 3625.
Fragmentation is a method of breaking down large (>MB) events into smaller
pieces and send them through the shared memory buffers, reassembling them at the
output. In the past this was only possible for periodic events (such as large
histograms read out once every few seconds), but now this is also possible for
polled events.

For the record, the MIDAS (& co) forums have been physically moved from
dasdevpc.triumf.ca to our new server machine ladd00.triumf.ca. This change
should be transparent to all users, but if anything stops working, please let me
know at olchansk-at-triumf-dot-ca. K.O.

INT idle (EQUIPMENT * pequipment)

Hi, Giorgio - I think you encountered a fundamental problem with what to do at the begin of 
run. There are two ways of thinking about it.

Some experiments want to start the run as quickly as possible, so they do not want 
begin_of_run() to do too much stuff.

Other experiments want to record all the current settings and conditions before starting a 
run, their begin_of_run() will read all the slow controls, interrogate all the power supplies, 
read all the voltages, temperatures, pressures, etc. By necessity this will slow down the 
starting of the run quite significantly.

The best I understand the midas class driver structure, it is more geared for the first case - 
fast starting of runs.

The thinking behind this choice considers the nature of most slow control data in typical 
physics experiments:
- if the data does not change quickly (say, room temperature, atmospheric pressure, etc), 
and you read it say every 1 minute, then you do not need to read it again at begin run time - 
the 1 minute old measurement is still good enough - nothing changed much since then
- if the opposite is true, the data changes wildly (i.e. detector high voltage current goes up 
and down in response to the quickly changing beam current), measuring it at the start of 
the run does us no good - by the time the first event comes around, it has already changed 
completely.

Hopefully Stefan can help you with your specific problem, he has better understanding of 
the midas class drivers.


K.O.


[quote="Pintaudi Giorgio"]Hello!
As you know, the generic MIDAS frontend has a class driver, device driver, bus driver
structure. Assuming a slow device frontend, its class driver should have a routine of type   
[CODE]INT idle (EQUIPMENT * pequipment)[/CODE]
This routine is called with a rate controlled by the 
"[I]/Equipment/<frontend name>/Common/Event limit[/I]" parameter.
The idle routine usually reads one channel of the frontend and stores the results
in the "[I]/Equipment/<frontend name>/Variables[/I]" ODB folder.

[B]My question is: it is possible to force (from the code) the frontend to call the idle routine 
at a 
certain point. This is because I need to update the "[I]/Equipment/<frontend 
name>/Variables[/I]"
variables inside the "[I]begin_of_run[/I]" routine, at a very specific time.[/B]

One dirty solution would be to increase a lot the reading rate ... but I need this
increased reading rate only during the run start while I need a low reading rate
during the run. So the question: is it possible to increase and decrease the reading
rate (event limit) of a frontend without stopping and restarting it?

If you need more info, please let me know.
Thank you
Giorgio[/quote]

@@ -411,6 +411,17 @@ static INT register_equipment(void)
             ss_sleep(3000);
             return 0;
          }
+#ifdef WAGASCI_OPEN_ODB_HOTLINK
+         status = db_open_record(hDB, hKey, eq_info, sizeof(EQUIPMENT), MODE_READ,
+                                 nullptr, nullptr);
+         if (status != DB_SUCCESS) {
+            printf("ERROR: Cannot open hotlink with equipment record \"%s\", db_open_record() status %d\n",
+                   str, status);
+            cm_disconnect_experiment();
+            ss_sleep(3000);
+            return 0;
+         }
+#endif
       } else if (status == DB_STRUCT_MISMATCH) {
          cm_msg(MINFO, "register_equipment", "Correcting \"%s\", db_check_record() status %d", str, status);
          db_create_record(hDB, 0, str, EQUIPMENT_COMMON_STR);

• Every change to the equipment "/Equipment/<frontend name>/Common" is instantaneously applied (and might crash the frontend?)
  

INT idle (EQUIPMENT * pequipment)

> We had a case where a detector produced electrostatic discharges which only lasted for a second or so
> and we were happy to detect this in spikes in the HV current. With measurements of only one per minute
> we would not have realized that so quicky.

For the T2K/ND280 TPC we implemented something similar. The TPC uses MicroMegas detector which sparks during 
normal operation. We asked Wiener/ISEG to implement a "spark counting mode" for us (and they did). In this mode,
high voltage over-current (a micromegas spark) sets a special flag (does not trip the high voltage). Our midas frontend
reads this flag at rate about 1/min, if flag is set, clears it, increments the software spark counter, reads the flag again,
if the flag is still set (failed to clear), it means this was not a normal spark but a high voltage breakdown
and the offending channel is shut down. I believe this mode is still part of the ISEG normal firmware.

Because the Wiener/ISEG interface uses SNMP to "read all data in one operation", the MIDAS "device driver" structure
was not useful, the readout was a simple loop, the readout frequency was easy to control, and indeed,
we read the high voltage with increased frequency during ramping. This was easy to implement because we
did not have to fight the MIDAS "device driver" framework.

If you want a similar solution, talk to the device, interpret the data, record values to odb and history, generate
midas events - all without hand holding from (arm wrestling with the rest of) midas - I recommend
the new tmfe.h/tmfe.cxx c++ frontend - see the two examples in midas/progs/fetest_tmfe.cxx
and fetest_tmfe_thread.cxx (single-threaded and multi-threaded).

K.O.

If the MIDAS Alarm property "write elog message" is enabled, an uninitialized variable "tag" is passed to 
el_submit() and depending on your luck, cause a crash. "tag" is supposed to be and is now a NUL-
terminated string. The only other use of el_submit() is in mhttpd.cxx and mserver.c, where it is called 
correctly.

alarm.c svn rev 5361
K.O.

In some experiments (i.e. DEAP), we see spurious symlinks to midas.log scattered just about everywhere. I 
now traced this to an uninitialized variable in cm_msg_log() and it should be fixed now. K.O.

I just realized that db_set_value, db_set_data, db_set_num_values and 
db_merge_data do not check for num_values == 0. With such a parameter the 
ODB can become corrupted, since zero length ODB entries are not allowed. I 
fixed the according places in odb.c and committed the changes. Everyone 
with ODB corruption problems should update that code.