MJ400215A1
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1. Foreword
This document describes the specifications and handling of the RS-485 communications
function installed as a standard feature in EX-250S.
The wiring, installation and operating procedures, other than communications, are
presented in a separate instruction manual. Prior to use, please read it also.
2. Switching to “control by digital communications”
(Mass flow controller only)
EX-250S has been set to “control by analog input” in the factory.
When you require “control by digital communications”, first change the flow rate
setting method to “digital (0)” in accordance with the procedure described below. To
return to “control by analog input”, change it to “analog (1)” again.
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Reference 5. Command Details 21) WFSM: Setting of the flow rate setting method
When the valve open/close input (analog signal) is “CLOSE” (fully close) or “OPEN”
(fully open), the equipment follows it regardless of the setting of the flow rate setting
method. Only when “CONTROL”, the action is switched over according to the
setting of the flow rate setting method as shown on the next page, but a difference
in action due to a difference in setting is limited to this part and others remain the
same. The flow rate control range is 2% to 100% of the full scale. The setting less
than 2% is “CLOSE”.
