8
Master Interlock Input
The Interlock input i the center terminal of a BNC connector located on the back panel of the HVS448. The interlock ignal i
TTL-compatible (0–5 V) and weakly pulled to 5 V via an ~20 kΩ internal re i tor. When the interlock ignal i in it high tate (>0.8
V), the high voltage connector are di connected from the power upply by relay , and the internal high voltage upply i turned
off. Becau e of the internal pull-up, a high tate can be maintained by leaving the ignal open.
High voltage i enabled by maintaining a TTL low ignal (<0.2 V) to the interlock. Thi can be accompli hed by connecting the
upplied 50-Ω terminator (Figure 2) to the interlock connection, connecting to an interlock witch to ground, or connecting to a
digital interlock ignal that i active low.
To te t if the interlock i ati fied (low): on the front panel click the Enable then All button . If the interlock i ati fied thi will
enable the high voltage and turn on a green light over the All button. If the light i red, the interlock i not ati fied.
Figure 2. 50-Ω
BNC Terminator for Interlock
Disable/Enable High oltage
Di abling high voltage i a quick way to place the y tem in a “ afe” tate. The high voltage connector on the back panel will
float to the driving voltage when di abled, regardle of the equence or the tate of other channel . High voltage can be
enabled or di abled from the oftware or u ing front panel control . Thi etting i nonvolatile and i remembered on power-up
.
Disable High oltage:
•From the front panel, pu h Disable, then All;
•or, from the oftware click the Disable High oltage toolbar button or , choo e Actions>Disable High oltage.
When the high voltage i di abled the LED over the ALL button will turn off, or will glow red if the Interlock i not ati fied.
Enable High oltage:
•From the front panel, pu h Enable, then All;
•or, from the oftware, click the Enable High oltage toolbar button or choo e Actions>Enable High oltage.
When the high voltage i enabled the LED over the ALL button will glow green if the interlock i ati fied or red if the Interlock i
not ati fied.
High oltage Connections
Each channel of the HVS448 include a ingle high voltage connector. Each channel can function a a voltage/current ource or
monitor, o thi connector act a either an input or output, depending on the function of the channel at any time.
The total y tem output (all channel con idered) will not exceed the maximum unit current ( ee Table 1). The y tem will
automatically hut down the high voltage upplie if thi current i exceeded. Each channel’ maximum and minimum voltage
and current can be limited in oftware to protect external device and equipment ( ee Channel Output Limits). Under no
condition will the voltage or current at the channel connection exceed the e oftware limit .
WARNING: DO NOT connect or disconnect cables from an enabled high oltage channel. Doing so could result in
personal injury and/or damage to the HVS448 or external equipment. You must disable the high
oltage connectors or turn off the HVS448 before plugging or remo ing equipment. Use the Disable
HV button on the toolbar or select Actions> Disable High Voltage from the dropdown menu tab.
WARNING: Do NOT connect a high oltage channel to a digital input or output. While the digital inputs and
outputs are protected to 115 VAC, connecting these different oltage le els could damage the HVS448
and/or any connected equipment.
