Metasys TC-9100 Series, Technical Bulletin

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Technical Bulletin—TC-9100 Universal Controller 33
PV = Process Variable
OCMx = Output Control Module Loops 1 and 2
PBx
= Proportional Band Loop 1
PBx
+1
= Proportional Band Loop 2
WSPx = Working Set Point Loop 1
WSPx
+1
= Working Set Point Loop 2
HILx = High Limit Loop 1
LOLx = Low Limit Loop 1
HILx
+1
= High Limit Loop 2
LOLx
+1
= Low Limit Loop 2
WSPx
+1
WSPx
0
100
Output
(OCMx)
Input (PV)
Loop 2 active Loop 1 active
LOLx
+1
LOLx
HILx
+1
HILx
PBx PBx
+1
Figure 12: Heating/Cooling PI Controller – Single Output
The single output controller is used when the same equipment is
modulated for heating and cooling, for example, a fan speed controller
(where the Heating and Cooling modes are controlled by another
controller). When there is separate equipment for heating and cooling, for
example, a heating valve and a cooling valve, a dual output
heating/cooling controller must be used (Algorithm 6).
When a programmable module is configured as Algorithm 5 (Item
PMxTYP, bits 5…1 = 00101), the module works with the next
programmable module (PMx
+1
) as a heating/cooling on/off controller
with a dual output. The output of the first module (Loop 1) is active when
Loop 1 is active, and is set to 0% when the loop is not active. Similarly,
the output of the second module (Loop 2) is active when Loop 2 is active,
and is set to 0% when the loop is not active.
Otherwise, the function of the algorithm is identical to Algorithm 3.
When a programmable module is configured as Algorithm 6 (Item
PMxTYP, bits 5…1 = 00110), the module works with the next
programmable module (PMx
+1
) as a heating/cooling PI controller with a
dual output. The output of the first module (Loop 1) is active when Loop
1 is active, and is set to 0% or to the Low Limit (whichever is lower)
when the loop is not active, setting also the Integral Term to zero.
Similarly, the output of the second module (Loop 2) is active when
Loop 2 is active, and is set to 0% or to the Low Limit (whichever is
lower) when the loop is not active.
Otherwise, the function of the algorithm is identical to Algorithm 4.
Algorithm 5:
Heating/Cooling
On/Off Controller
–
Dual Output
Algorithm 6:
Heating/Cooling
PI Controller –
Dual Output