FEMTO Variable Gain Low Noise Current Amplifier¶

The equipment is a Variable Gain Low Noise Current Amplifier. The above document is the datasheet, which gives some hints on its use. The only type tested with the bliss - femto module was the type in the datasheet, a dlpca-200.

The controller is connected to a WAGO controller, which in turn changes the levels on the controllers analog inputs.

Control¶

The controller implements a number of properties.

The control is implemented through the WAGO Tango device server.

Wagobox modules:¶

“standard” for a Femto:

750-554: 2 Channel 4/20mA Output for two offsets
750-519: 4 Channel Digital Output for 3 gains and one gain
750-414: 4 Channel Digital Input for overload

No other configurations were present in the developement system.

Configuration¶

Yaml file(s) in ~blissadm/local/beamline_configuration allow to set the signal names used in the wago controller config:

plugin: bliss
class: femto
list:
  - name:     femto1
    wago:     idxx/wcidxxc/tg
    type:     dlpca
    offset:   f1oset  # (1)  750-556
    gain:     f1gain  # (3)  750-519
    range:    f1hilo  # (1)  750-519
    overload: f1ovl   # (1)  750-414
    coupling: dc
    # possible other values could be:
    # coupling: f1acdc
    # coupling: dc
    # coupling: ac
    # bandwidth: f1bw10 f1bw1

  - name: femto2
    wago: $wcid99d
    type: dlpca
    gain:     f2gain
    range:    f2hilo
    overload: f2ovl

Usage¶

The controller implements a short list of properties:

Properties¶

‘offset’¶

‘coupling’¶

Can be set to ‘ac’ or ‘dc’. It will, however, have no incidence on the usage.

‘gain’¶

‘range’¶

‘overload’¶

‘bandwidth’¶

Should a controller not implement all signal, the property will return None.

In practice, with the controller defined as example in the above mentioned configuration, one would read the gain as follows:

BLISS [6]: print("%g\n" % femto1.gain)
1e+10

and set it accordingly:

BLISS [7]: femto1.gain = 1e4
BLISS [8]: print("%g\n" % femto1.gain)
10000

The offset would be set to values between 0 and 10.

The coupling would be set with the words “ac” or “dc”.

The gain is a value allowed by the controller, for the dlpca it should be a value like 10e3 (1e4) to 10e11 (1e12):

Gain setting for dlpca-200
Low noise	High speed
Pin 14=HIGH	Pin 14=LOW	Pin 12	Pin 11	Pin 10
Gain (V/A)	Gain (V/A)	MSB		LSB
10e3	10e5	LOW	LOW	LOW
10e4	10e6	LOW	LOW	HIGH
10e5	10e7	LOW	HIGH	LOW
10e6	10e8	LOW	HIGH	HIGH
10e7	10e9	HIGH	LOW	LOW
10e8	10e10	HIGH	LOW	HIGH
10e9	10e11	HIGH	HIGH	LOW

The range would be set with the words “low” or “high”.

Overload is read only.

Bandwidth must be set with one of “Full”, “1MHz” or “10MHz”.