Jan 2012
T190 Iss.2
Page 32 of 38
10.
Options
10.1.
Volt free alarm relay (BMS)
All touch screen incubators are fitted as standard with a volt free changeover relay for connection to a
building maintenance system (BMS).
This relay changes state whenever the incubator is in an alarm condition. The relay changes back to its
original state once the alarm condition clears.
The connections are as shown below:
10.2.
4-20mA retransmission (RETX)
This is an option that must be specified at the point of ordering.
This feature allows the chamber temperature and CO
2
process values to be retransmitted as a 4-20mA
signal. This 4-20mA signal can be connected to external equipment for independent validation of incubator
performance.
The incubator will be supplied with a pre-wired 3 metre cable socket.
The temperature signal is scaled as: 4mA = 0°C; 20mA = 250°C
The CO
2
signal is scaled as:
0mA = 0% CO
2
;
20mA = 20% CO
2