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15.1.4
"Watchdog" function, monitoring the serial
data flow
The following applies to situations where the watchdog function is
enabled (see Namur instructions). If no new transmissions of
these commands from the PC take place within the preset watch-
dog time, the heating and stirring functions will be shutdown
according to the watchdog mode selected or will be controlled
using the preset setpoints. An operating system crash, a PC
power failure or a fault in the connecting cable to the
RET control / t can cause an interruption in data transmission.
"Watchdog" Mode 1
If an interruption in data transmission occurs which is longer than
the preset watchdog time, the heating and stirring functions will
be shutdown and the error message ER 2 will be displayed.
"Watchdog" Mode 2
If an interruption in data transmission occurs which is longer than
the preset watchdog time, the speed setpoint value will be set to
the WD safety speed setpoint and the temperature setpoint will
be set to the WD safety temperature setpoint. The WD warning
message will be displayed.
15.2
Connections between DIGITAL-T
and external devices
The RET control / t unit can be connected to other external devices
using the following IKA adapters and adapter cables.
022009
15.2.1
PC 5.1 Adapter IKA - Control
An adapter cable is available as an accessory part. It splits the ana-
log and serial signals. The analog output signals are allotted to a 7-
polar coupling according to the NAMUR-recommendation; the
serial signals to a 9-polar Sub-D-bushing plug (RS 232 C).
2
5
4
1
3
6
7
2 Temperature
3 Analog GND
5 Speed
15.2.2
PC 2.1 Cable
Cable PC 2.1 for connection to the 9-pin socket on the computer.
1
RxD 2
TxD 3
Magnetic stirrer
Magnetrührer
4
GND 5
= plug
= Stecker
6
RTS 7
CTS 8
9
15.2.3
PC 1.5 Cable
Cable PC 1.5 for connection to the 15-pin socket on the computer
(25-pin plug).
5
4 3 2
1
9
8 7 6
2 R x D
3 T x D
5 RS 232 GND
7 RTS
8 CTS
1
2 RxD
3 TxD
PC (processor)
4
PC (Rechner
5 GND
= bushing
= Buchse
6
7 RTS
8 CTS
9
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