Data Sheet for Product

Technical Instructions RL 243 A Commercial Duty Analog Relay
Document Number 155-107P25
Rev. 1, April, 2000
Page 4
Siemens Building Technologies, Inc.
Figure 3. Ratio Relay 2 in = 1 out.
OPERATIONAL FORMULA:
T- TR- R
Since TD is zero, and TR = T
Then T = R
2
Operation,
Continued
Ratio Relay 2 In = 1 Out
Output pressure is equal to one-half the input pressure. A separate air supply can be
omitted by connecting the input pressure to both T and S ports.
OPERATIONAL FORMULA:
TD + T = R
Since TR is zero.
Input #1
T (psig)
Input #2
TD (psig)
Output
R (psig)
055
459
12517
8715
51116
Figure 4. Summing Relay or Adjustable
Advancing Relay.
R cannot be greater than S.
Summing Relay or
Adjustable Advancing
Relay
Output pressure is equal to the total of both inputs so relay can be used as a summing
relay. If one input is fixed, and the other is adjustable, the relay can be used as an
adjustable advance relay.
Input Output
T TR&R
(psig) (psig)
0 0
2 1
8 4
16 8
24 12
R cannot be greater than S, and
T – TR cannot be less than 0
psig.
Discontinued