aci eRCM Express, Руководство пользователя

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mCore Firmware Ver 01.10 Ver 2019-Oct-29 Page 49 of 97
Relax eRCM Limits to Station Limits:
When implementing a compressor model in a Unit Control Panel environment, end-user
should set certain limits within the model so that those limits do not trigger an invalid
condition before the PLC would trigger an invalid condition.
•
Example 1: If the PLC alarms at a discharge temperature of 300 °F and shut downs
at a discharge temperature of 325 °F, then the maximum allowed discharge
temperature in the eRCM Viewer model should be 325 °F, and not 300 °F.
•
Example 2: If the unit is allowed to go down to 40% torque, then make sure that the
Min Allowed Torque setting in the eRCM Express is 40% or lower.
The goal is to not have the eRCM Express trigger unnecessary shut downs by indicating
all load steps as unsafe, when in fact they may still be within the PLC’s limits.
Using Compressor to Pack a Discharge Line:
If the unit needs to pack a discharge pipe that has fallen below its normal minimum
discharge pressure, then ensure that the following limits are set in the eRCM Viewer model
being used in the eRCM Express unit:
•
Minimum Compression Ratio = 1.00
•
Minimum Discharge Pressure = Minimum Suction Pressure
Running Unit at Low Torque:
If the unit needs to occasionally run in low torque conditions, then make sure that in the
eRCM Viewer model being used:
•
Minimum Torque = A number from 1% to 60%.
Typical Default for Motors is 25%, and Typical Default for Engines is 60%.
Running Unit when Discharge Pressure is Less Than Suction Pressure:
If the unit needs to occasionally run when the discharge header pressure is less than the
suction header pressure, then:
1) Make sure that this is okayed by the OEM. Operations in blow-through can
potentially significantly degrade the life of compressor valves.
2) eRCM Express is not useful for determining unit safety under these conditions
(blow-through). So, if that mode is ok with the OEM, then to keep eRCM Express
from indicating operating issues, simply set the Discharge Pressure equal to the
Suction P5 psi. Thus, if Ps=390 psiG, and Pd=3
4 0 psiG, when sending data
to eRCM Express, simply send 390 for Ps, and 395 for Pd.