Agilent Technologies Agilent 3499A, Руководство пользователя

Страница: 206 / 357

206
Chapter 7 Plug-in Modules
N2267A 8-Channel High Current GP Module
7
N 2267A 8-C h an n el H igh C u rren t G P M odu le
The Agilent N2267A is an 8-Channel High Current GP module typically
used in mobile phone battery test applications. It can switch up to 8 A at
250 Vac or 5 A at 30 Vdc, with decreasing current to 1 A at 125 Vdc.
The module includes temperature control and protection circuitry,
designed to prevent the module temperature from rising too high. The
N2267A can potentially be switching up to 64 A (8 channels at 8 A). The
temperature control circuitry prevents dangerous overheating.
The 8 channels of the N2267A are independent, more than one channel
can be closed or opened at the same time.
Caution Exceeding the maximum switching current of 8 Ampere on any channel
will damage the N2267A module and possibly the system.
Specifications for the N2267A are given on page 317.
Temperature Control
The temperature control circuitry includes two sensor ICs and a cooling
fan. When the temperature of the N2267A reaches 45
o
C (113
o
F), the
cooling fan on the module turns on. If the temperature drops below
40
o
C (104
o
F), the fan turns off.
Over-temperature Protection
If the module temperature rises to 75
o
C (167
o
F), all channels on the
module are opened and a TTL-level warning output (connected via SMB)
on the rear panel will change from high to low. This output can be used
to drive an external LED or buzzer. The warning output will reset
(change from low to high) when the module temperature drops below
59
o
C (138
o
F).
The over-temperature protection is controlled by hardware logic on the
module. Therefore, if the over-temperature protection has opened all the
channels on the module, the mainframe front-panel and system memory
will still indicate the original state of the channels. To regain control of
the channels, you must cycle the power to the module (reset and channel
commands will not work). Note that cycling power to regain control will
only work if the module temperature has dropped below 59
o
C (138
o
F)
otherwise the protection circuitry will be activated again.