Ulvac C30HVRT - Figure 2-8 Signal Delay When Powered On（In Alternate Operating Mode; Figure 2-9 Signal Delay When the Time Period from a Stop to a Restart Is Short

C30HVRT Compressor Instruction Manual
INPUT POWER SUPPLY
COMP・CRYOCOOLER
START/STOP
COMP・CRYOCOOLER
ACK
COMP OPERATION
Figure 2-8 Signal delay when powered on（In Alternate operating mode）
CRYOCOOLER OPERATION
In the cases of (b) and (c), the answer-back signal is also delayed for a maximum of 5 seconds to
respond to the command of “COMP RUN”. This is because the compressor pump waits to
begin its operation until the helium pressure inside becomes stable. For references, Figure 2-9
shows the signal delay occurred in Alternate operating mode when the time period from a stop to
a reboot is short, and Figure 2-10 shows the timing chart of C30HVRT when a short power
interruption has occurred in Momentary operating mode.
From the above-mentioned, the set value of the timeout of the answer-back signal should be
determined based on the condition in which only the compressor has detected a short power
interruption although a user’s equipment is not detecting it because of differences of the
specifications. In this condition, the equipment must recognize that the compressor is out of
order because the equipment side can't receive the answer-back signal. If dispatch of the
answer-back signal will be late for a preset timeout time even if the compressor has restarted
after recovery of the input power, an alarm of a stop will come out.
Therefore, be sure to set the timeout time of an answer-back signal as 8 seconds or more in
order to monitor the operating conditions of the compressor correctly.
Note: Figure 2-10 leads the following equation:
td + tw + 1 <= 2+ 5 + 1 = 8 (seconds)
Where, “1” second is a margin added.
COMP・CRYOCOOLER
START/STOP
COMP・CRYOCOOLER
ACK
COMP OPERATION
CRYOCOOLER OPERATION
Figure 2-9 Signal delay when the time period from a stop to a restart is short
(In Alternate operating mode)
ULVAC CRYOGENICS INCORPORATED 2-11