Instructions

Intesis
TM
INMBSPAN001I100
User’s Manual r1.2 EN
© HMS Industrial Networks S.L.U - All rights reserved
This information is subject to change without notice
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13 / 22
• AC unit external temperature reference (Modbus) (R/W)
(register 22 – in Protocol address / register 23 – in PLC address):
This register allows us to provide an external temperature reference from the Modbus
side. Panasonic indoor unit does not allow on devices like INMBSPAN001I100 to provide
directly temperature to be used as a reference of the control loop of the AC indoor unit.
In order to overcome this limitation and enable the usage of an external temperature
sensor (i.e. in Modbus side), INMBSPAN001I100 applies the following mechanism (only if
“external temperature’s reference” is being used):
o After a couple of values have been entered in the “AC unit external temperature’s
reference” (register 22/23) and “AC unit temperature set point” (register 4/5),
INMBSPAN001I100 is going to estimate the temperature chosen implied (e.g. if a
“temperature setpoint (register 4/5)” of 22ºC, and an “external temperature
reference (register 22/23)” of 20ºC are entered, INMBSPAN001I100 will assume
that the user is demanding a +2ºC increase in temperature).
o By knowing at any time the ambient temperature currently used by the indoor
unit to control its own operation (register 5/6), INMBSPAN001I100 can calculate
the required temperature setpoint needed to apply the decrease/increase on the
real temperature and reach the temperature chosen by the user (following the
example above, if INMBSPAN001I100 reads an “ambient temperature” (register
5/6) of 24ºC in the indoor unit, it will apply a final setpoint of 24ºC + 2ºC =
26ºC).
o At this moment, each time that INMBSPAN001I100 detects a change on the
ambient temperature reported by the indoor unit (register 5/6), it will also change
the required setpoint, in order to keep the temperature required by the user at
any time. If we follow the last example, if INMBSPAN001I100 receives a new
temperature´s value coming from the indoor unit of 25ºC, INMBSPAN001I100 will
automatically adjust the temperature setpoint required of the AC indoor unit to
25ºC + 2ºC = 27ºC).
o In general, INMBSPAN001I100 is constantly applying the “Virtual Temperature”
formula:
S
AC
= S
u
– ( T
u
– T
AC
)
Where:
S
AC
- setpoint value currently applied to the indoor unit
S
u
- setpoint value written at Modbus side (register 4/5)
T
u
- external temperature reference written at Modbus side (register 22/23)
T
AC
- ambient temperature that the indoor unit is using as the reference of its
own control loop (register 5/6)
When INMBSPAN001I100 detects a change in any of the values of
{ S
u
, T
u
, T
AC
}, it will send the new setpoint (S
AC
) to the indoor unit.
o After the startup, the value for “external temperature’s reference” (register
22/23) has a value -32768 (0x8000). This value means that no external
temperature reference is being provided through INMBSPAN001I100. In this
scenario, the setpoint value shown in register 4/5 will always be the same as the
current setpoint value of the indoor unit.
o Notice that, the use of the “external temperature reference” (register 22/23)
(e.g., writing a value different from -32768 / 0x8000 in it) has the following
relevant consequences: