This example SWMM 5 model closes a weir based on the depth at the upstream node of the Weir every 0.25 feet.  You can see the effect of the RTC rules using a Scatter plot of Weir Flow versus Weir Depth in SWMM 5 (Figure 1).   The Weir flows normally every 0.25 feet but shuts down three times using these rules which set the Weir Setting to 0.0

RULE Weir100

IF Node  WeirNode Depth > 1.75

AND Node WeirNode Depth < 2.0

THEN WEIR WEIR Setting = 0.0

Priority 2

RULE Weir101

IF Node  WeirNode Depth > 2.25

AND Node WeirNode Depth < 2.5

THEN WEIR WEIR Setting = 0.0

Priority 2

RULE Weir102

IF Node  WeirNode Depth > 2.75

AND Node WeirNode Depth < 3.0

THEN WEIR WEIR Setting = 0.0

Priority 2

RULE Weir103

IF Node  WeirNode Depth > 3.25

AND Node WeirNode Depth < 3.5

THEN WEIR WEIR Setting = 0.0

Priority 2

RULE Weir104

IF Node  WeirNode Depth > 3.75

AND Node WeirNode Depth < 4.0

THEN WEIR WEIR Setting = 0.0

Priority 2

Figure 1.  Scatter Graph of Weir flow versus Weir Node Depth.