RL 243 MP Multi-Purpose Relay
Technical Instructions
Document Number 155-042P25
September 10, 2018
Siemens Industry, Inc.
Page 3
Application
The multi-purpose relay is factory calibrated with a 15 psi spring adjustment for reverse
acting service. However, the multi-purpose relay provides a number of specific control
actions which are frequently utilized in control systems. Some of the typical applications
where this relay can be applied are as follows. Additional applications can be obtained
depending upon how it is piped and applied with other devices in a single system.
•
Direct acting amplifying (See Figure 2).
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Reverse acting amplifying (See Figure 3).
•
Lower pressure transfer relay (See Figure 4).
•
Signal advancing relay (See Figure 5).
•
Minimum pressure relay (See Figure 6).
•
DA or RA limit control (See Figures 7 and 8).
•
Signal inverting relay (See Figure 9).
•
Characterized minimum pressure relay (See Figure 10).
Direct Acting (DA)
Amplifying Relay
Output pressure will vary directly with input pressure. Relay is fail-safe and cannot
generate an output signal unless a source of air is available at S-port (Figure 2).
Figure 2. Direct Acting (DA) Amplifying Relay.
