Instruction Manual
ExTox IMC-8/-4
Page 12 of 24
BA_IMC-8_-4_e_2011-09-20.doc
5.2
Type Biogas
5.2.1
Functions
▪
Course of Biogas-Measurement
During operation mode "BIO" discontinuous measurement takes place. All channels for biogas
measurement are selected in the menu Channel Configuration by setting the mode TIMER.
Three phases are run through cyclically:
1.
Air: the gas flow is flushed with air that means the magnetic valve has switched to the inlet
test gas / flushing air.
2.
Flushing: the system switches to the measured gas inlet. The gas concentration is not
measured during this time. This phase is needed to transport the sampled gas from the
process to the IMC using the gas flow. The gas suction pump is switched off two minutes
before end and the gas flow is closed. Measurement in batch mode is prepared.
3.
Measuring: the system measures the actual values when changing over to phase measure-
ment. During this phase the gas suction pump remains switched off.
You can manually interfere in this process. Measurement can be started by pressing simultane-
ously the keys F8+F3 (IMC-8D) or F6+F3 (IMC-4D). The IMC-Biogas first changes to the phase
flushing and starts the measurement later on.
For measuring points in TIMER Mode all measured values, alarms and outputs remain frozen on
the latest value of the previous measuring phase during the phases "air" and "flushing". Latch-
ing alarms can only be reset during measuring phase.
Attention:
This means that reset will be
possible in the next phase. If necessary measurement can be started manually (see above) to
reduce the waiting time on longer cycle times.
The times for the individual phases can be adjusted in the menu Timer which can be reached
via the menu System Parameter and selection of the menu setting Mode BIO.
▪
Monitoring of Ambient Air
Channels which are not needed for the IMC measurement can easily be used for a continuous
monitoring of ambient air. Performance of these channels corresponds to the normal measuring
operation of the control unit. Channels for monitoring of ambient air are also activated in the
menu Channel Configuration by setting the Mode ON.
▪
Status Monitoring
The following status monitoring functions are integrated in this version:
rotary speed monitoring of both fans
flow rate monitoring: message for over- and under-scale of nominal range
temperature monitoring of the measured gas cooler (if installed)
In the first two cases a message leads to system fault of the control unit.
As long as the measured gas cooler does not reach its operating temperature, for example dur-
ing the warm-up phase after initial operation, the gas suction pump remains switched off.
5.2.2
Parameter Settings
▪
System Parameter
In the menu System Parameter the operation mode "BIO" instead of "ET-8" and "ET-4" is fac-
tory-sided activated.
Attention:
Changing of these settings should in no way be done by the user. Changed meas-
uring functions may otherwise lead to loss of safety functions.
In the submenu BIO the following changes can be performed.
Access Level to perform changes within the Menu Timer: 3
