Thermo Scientific Dionex ICS-2000, Operator'S Manual

Page: 359 / 390

D • TTL and Relay Control
Doc. 031857-03 4/06
D-5
The action of the positive (rising) edge depends on the function: For
the
Load/Inject function, the rising edge switches the injection valve
to the Inject position. For the
Pump On
function, the rising edge turns
off the pump (and suppressor). For Autozero and Mark , the rising
edge has no effect.
•
Inverted Edge : The inverted
edge mode works identically to
the normal edge mode except
that the positive and negative
edges are reversed in function.
•
Normal Pulse : In normal pulse
operation, the negative (falling)
edge of the TTL signal is the
active edge and the positive
(rising) edge is ignored.
A pulse width of 50 ms or more
is guaranteed to be detected. A pulse width of 4 ms or less is
guaranteed to be ignored. The action for pulse widths that are greater
than 4 ms and less than 50 ms is undefined.
•
Inverted Pulse : The inverted
pulse mode operates identically
to the normal pulse mode
except that the positive and
negative edges are reversed in
function.
D.2 Controlling TTL and Relay Outputs
The ICS-2000 provides two TTL outputs and two relay contacts for control of
functions in external devices, such as an integrator or autosampler. The relay
outputs can be used to switch any low-voltage control. Switched current must be
less than 200 mA and 60 V peak blocking. The relay-contact closures are
normally open. When the relay is closed, current flows to the connected device.
Relay loads in excess of 200 mA or with included power supplies over
60 V may damage the relay drivers on the CPU.