Interfaces and software update
OPERATION MANUAL
Chapter 6
Unistat® T300 Series
Liability for errors and misprints excluded.
V1.2.0en/12.05.15//14.06
70
be changed by the operator at the temperature control unit at any time. A change from an open
to a closed contact does not cause any change and the temperature control process is not reset to
the original setpoint.
▪
“Second setpoint selective”:
An open contact causes a thermoregulation to its original setpoint.
An closed contact causes a thermoregulation to the second setpoint.
▪
“Internal / Process”:
If the contact is open, the device-internal temperature sensor is used for
control. If the contact is closed, the additionally connected external temperature sensor is used
for control. Switching the contacts open/closed or closed/open switches between these two tem-
perature sensors.
▪
“Temperature control on/off”:
The temperature control process starts when switching from an
open to a closed contact. The temperature control process switches off when switching from a
closed to an open contact.
▪
“Release”:
The temperature control process switches off, if the temperature control process is
active and the contact is switched from closed to open. The temperature control process is
not
switched on
, if contact is further switched from open to closed!
The interface is specified as a digital input. Do not apply voltage or current.
Pin
Signal
1.3 E2
2
E1
6.2.1.3
Conccector POKO ONE (floating contact) alarm
Signal contact for external monitoring.
Notice the functions provided by PoKo in the category “Interfaces”. The potential-free contact
(PoKo) signals the state of the temperature control unit via the contact position. A closed operating
contact means readiness for operation. If a fault or an error occurs, the operating contact is opened
(this applies to the make contact between pin 1 and pin 2).
The following settings are offered:
▪
“Off”:
The POKO displays the OK state whenever the temperature control unit is ready for opera-
tion. The unit is ready for operation about 30 seconds after switching on, once the internal con-
troller check has been completed. The OK status is terminated by switching off the unit or in case
a fault occurs.
▪
“Internal temperature relative":
Set the upper and lower limit of a temperature range around
the setpoint by using the POKO “min. value” and the POKO “max. value”.
The potential-free contact indicates the condition, that the setpoint differs from the actual value
by a smaller difference than was defined by the temperature range. Exceeding the set range only
results in the potential-free contact to switch (away from the OK state), but does not result in fur-
ther reactions of the temperature control unit. The contact returns to the OK status if the actual
value is within that range.
▪
“External alarm”:
The POKO relay becomes active (OK state) in this function only, if the tempera-
ture control unit is switched on and is in “Fault” mode. The advantage is that the alarm will not be
triggered if the temperature control unit is switched off. Please use the POKO function
“OFF”
if
the alarm function is wanted together with the operating current principle.
▪
“Unipump/PCS”:
This POKO function and the enable contact of the pump guarantee that the
external pump runs synchronously with the circulation pump in the temperature control unit if an
external pressure booster pump is used in your temperature control circuit, i.e. the POKO as-
sumes the OK state as soon as the internal circulation is started up.
PCS: The POKO is used to communicate the state of the temperature control unit to the process
control system.
POKO condition
ON
means the pump is running.
POKO condition
OFF
means the pump is not running, the temperature control unit is in stand-by
mode.
▪
“Control via RS232”:
A special command on the serial interface is used to switch the POKO on and
off. Please also refer to the software offered by us.
▪
“Process temperature relative”:
Set the upper and lower limit of a temperature range around the
setpoint by using the POKO “min. value” and the POKO “max. value”.
Pin assignment
