Dear all,
I am using a DAQ card from national instruments 6071E to measure
analog values. It works fine but I have some problems changing the
range:
I found the a4l_find_range function and it works well, seeing the
range_info changes according to my wishes. But I realise that the only
function that uses the range information is the a4l_rawtod. It works
for the range conversion but technically the range is never changed on
the card itself (switching to another internal gain) and so the value
I coming out at the end is wrong (mismatch between the setting on the
io-card and a4l_rawtod).
Which function do I have to use or how to pass this information to the card?
Thanks for your answers in advance.
Cheers,
Thomas
My test program:
// simple build cmd: g++ test-pcimio.c -I/usr/xenomai/include/
-lxenomai -lnative -lanalogy -lpthread -lrtdm -L/usr/xenomai/lib
// execute #./a.out
#include <time.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <xenomai/analogy/analogy.h>
/*
* Initialization function, activated once by PolyORB (at startup)
*/
a4l_desc_t arm_device;
int ni_6071e_analog_channels[16] =
{0,1,2,4,5,6,16,17,18,19,21,23,32,33,34,35};
int range_settings[16] = {-5, -10, -10, 5,
5, 5, 5, -5, -5, -5, -5,
10, 10, 10, -0.5, 0.5};
a4l_chinfo_t *ni_6071e_analog_channel_infos[16];
a4l_rnginfo_t *ni_6071e_analog_range_infos[16];
int analog_init = 0;
void init_arm()
{
int i = 0;
int ret;
double Range_Value;
double Range_Max;
double Range_Min;
ret = a4l_open (&arm_device, "analogy0");
if (ret != 0)
{
printf ("[EXOARM] Error while opening the arm device, return
code=%d \n", ret);
return;
}
arm_device.sbdata = malloc(arm_device.sbsize);
ret = a4l_fill_desc (&arm_device);
if (ret != 0)
{
printf ("[EXOARM] Error while calling fill_desc(), return
code=%d \n", ret);
return;
}
for (i=0; i<16; i ++)
{
ret = a4l_get_chinfo (&arm_device, 0,
ni_6071e_analog_channels[i], &ni_6071e_analog_channel_infos[i]);
if (ret != 0)
{
printf ("[EXOARM] Error invoking a4l_get_chinfo on channel
%d, return code=%d \n", ni_6071e_analog_channels[i], ret);
}
ret = a4l_get_rnginfo (&arm_device, 0,
ni_6071e_analog_channels[i], 0, &ni_6071e_analog_range_infos[i]);
if (ret != 0)
{
printf ("[EXOARM] Error invoking a4l_get_chinfo on channel
%d, return code=%d \n", ni_6071e_analog_channels[i], ret);
}
}
//setting up the range
for(i=0;i <16; i++)
{
Range_Value = range_settings[i];
if (Range_Value < 0)
{
Range_Min = Range_Value;
}
else
{
Range_Min = 0.0;
}
Range_Max = abs(Range_Value);
ret = a4l_find_range
( &arm_device, //device
0, //subindex
ni_6071e_analog_channels[i], //idx channel
A4L_RNG_VOLT_UNIT, //unit
Range_Min,
Range_Max,
&ni_6071e_analog_range_infos[i]
);
if ((ret == -ENOENT) || (ret == -EINVAL))
{
printf("Error while configuring ranges 6071\n");
}
}//end for loop
analog_init = 1;
}
void arm_poll_acquisition_board()
{
int i;
double tmp;
int ret;
uint8_t raw[128];
if (analog_init == 0) {
printf("[arm] Runtime Error - Periodic task activated before
proper initialization.\n");
return;
}
for (i=0; i<16; i++)
{
ret = a4l_sync_read (&arm_device, 0,
ni_6071e_analog_channels[i], 0, &raw, 128);
if (ret <= 0)
{
printf("[arm] Error while acquiring the data\n");
}
ret = a4l_rawtod (ni_6071e_analog_channel_infos[i],
ni_6071e_analog_range_infos[i], &tmp, &raw, 1);
if (ret <= 0)
{
printf("[arm] Error while converting the data\n");
}
else
{
if(i != 0)
{
printf(";");
}
printf("%lf", tmp);
}
}
printf("]\n[");
return;
}
int main ()
{
init_arm ();
while (1)
{
arm_poll_acquisition_board();
sleep (4);
}
}
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