Agilent Technologies E6198B, Руководство пользователя

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Using the Pin Matrix Cards
6
E6198B Switch/Load Unit User Manual 6-7
Relay Timer
The Relay Timer indicates whether or not the last change to a
relay's state (opening or closing the relay) is complete. The
timer starts or restarts when a command to change a relay's
state is received. The timer stops when it times out after an
interval sufficiently long for a relay to change state.
If the relay timer's status is “busy,” as reported by bit 7 of the
Status Register (see
Appendix B ), relays may not yet be in the
desired state. If the status is “not busy,” then the relays have
reached their newly programmed state. The nominal time-out
value of the relay counter is 500
μ
s.
Column Disconnect Relay Control
Each of the four columns has a disconnect relay between it and
the Analog Bus. Depending on the state of bit 6 in the Control
Register (described in
Appendix B ), the disconnect relays are
either under manual or automatic control.
When in automatic mode, when you close a matrix relay, the
disconnect relay associated with that column also closes. When
in manual mode, the four column disconnect relays are
controlled by bits 3-0 in the Column Control & Protection
Bypass Register (described in
Appendix B ). Because manual
mode is used only when doing diagnostic checks, the default
control mode is automatic.
OAR
Bit 5 in the Control Register controls the OAR (“open all relays”)
feature, which immediately opens all relays on the card.
Because the bit is self-clearing, it does not require resetting.
OAR also clears bits 3-0 of the Column Control & Protection
Bypass Register. When executed, OAR re-triggers the relay
timer.
Reset
Bit 0 in the Control Register programmatically resets the card.
Resetting the card clears all internal registers, which resets all
board functionality to its default, power-up state. Resetting also
clears all relay registers, sets column disconnect relay control to
automatic mode, and starts the relay timer.