Operation 11
HP289
3.2.1 Control Relays
The two control relays can be set up to control a single valve or a dual
valve with slow-stop and/or slow-start. Alternatively, the second relay
can be used to control a pump.
The relay operation is shown on the previous two pages.
A time delay between the Batch Start and the time when Relay 2
energizes can be set to provide a soft start up. The delay can range
from 0 (no delay) to 79 minutes and 59 seconds.
A Prestop quantity (i.e., the quantity to the end of the batch) can also
be set to provide a slowdown of flow at the end of the batch, thereby
enabling precise quantities to be batched.
The process can be stopped at any time by pressing the STOP key,
whereby both relays will immediately de-energize. The process can
then be aborted and the batcher reset by pressing the STOP key again,
or the process continued by pressing the RUN key.
If the process is continued and the instrument was previously in the
slow-start or main control phases (i.e., not the prestop phase), the timer
will be reset and a slow-start will occur with a full time delay to ensure
a correct start up. The totals will not be reset and the batch quantity
will remain unchanged.