3.5.3 Single channel Inhibit
INFORMATION
INFORMATION
INHIBIT is an external signal, that switches off the high voltage for the device or a specific channel
The Sub-D connector on the bottom of the front panel allows to install an Inhibit for each channel. The pin assignment is
as follows:
Channel 0-5 / GND
0
1
2
3
4
5
GND
SUB-D9 connector pin
1
2
3
6
7
8
4
5
9
INHIBIT Option-ID: The INHIBIT pins are internally connected to the module GND via pull down resistors (approx. 10 kΩ).
This ensures that a disconnected cable always causes an interlock. HV generation according to the settings is only
possible if the corresponding INHIBIT pin is actively pulled to TTL High level.
INHIBIT Option-IU: The INHIBIT pins are internally connected to 5V via pull up resistors (approx. 10 kΩ). HV generation
according to the settings is possible with TTL High level or open INHIBIT pins. If the INHIBIT contact pin (n) is connected to
the module GND or a TTL-LOW potential for at least 100 milliseconds, an Inhibit signal is generated. The channel status
bit isExternalInhibit and the channel event status bit EExternalInhibit are set. One of the following reactions to this signal
can be programmed:
•
No Action (default)
•
Turn off the channel with ramp
•
Shut down the channel without ramp
•
Shut down all channels without ramp
These reactions can be programmed by the CAN interface, see chapter Delayed Trip in the
CAN EDCP Programmers-Guide
(see apenndix)
for reference.
When the INHIBIT is no longer active (TTL-HIGH potential or not connected), the Inhibit flag must be reset before the
voltage can be switched on again (
CAN EDCP Programmers-Guide (see apenndix)
).
3.6 The function "Delayed Trip"
3.6.1 Operating principle
The function "
Delayed Trip
" provides a user-configurable, time-delayed response to an increased output current (I
out
)
higher than the set current (I
set
). The response to this kind of event can be, for example, to ramp down the channel with
the programmed ramp. A detailed description for the configuration can be found in the
CAN EDCP Programmers-Guide (see
apenndix)
.
By a programmable timeout with one millisecond resolution, the trip can be delayed up to four seconds. During this time,
the output current is limited to the value of I
set
(constant current mode).
The hardware regulation signals, constant voltage (CV) or constant current (CC), are sampled every millisecond by the
microprocessor. Once the constant current mode is active, the programmed timeout counter is decremented. If the HV
channel returns to constant voltage mode before timeout (i.e. I
out
< I
set
), the counter will be reset. So this process can be
restarted if the current rises again.
To guarantee a sufficient resolution for the current set values, a nominal current adequate to the application should be
selected. iseg offers HV modules with nominal currents reduced to 100 μA in all voltage classes. These are designated e.g.
for semiconductor detectors, which only require a few microampere operating current.
NHS – NIM standard High Voltage Power Supply | Last changed on: 01.10.2018 |
www.iseg-hv.com
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