137
9 Appendix
9.23.3 Control Cabinet Wiring
The low-voltage cables from and to the ETAMATIC should not run in parallel to the power elec-
tronics' in and out conductors in one cable duct.
Frequency converter cables and switches/contacts carrying high inductive or capacitive firing
rates are particularly critical. Therefore, avoid routing parallel to the drive cables of solenoid
valves, ignition transformers, servo motors and similar devices.
Although this device exceeds all relevant EMC standards in some respects, suitable wiring is
essential to ensure that the entire system operates smoothly in all conditions.
Shielding of supply lines out of the field:
The best method of connecting supply lines out of the field (e.g. potentiometer line) is to con-
nect them directly (without additional terminals).
If you need additional terminals, you must connect the shielding beside this terminals
Avoid long distances in the cable duct.
9.24 Run to Shut-off Limits
Like every control system, the ETAMATIC has tolerances, which affect the accuracy of the set-
tings. You have influence of these tolerances of the ETAMATIC with the parameter settings.
When you adjust the combustion system, ensured that there is a safe and stable flame. To
verify this, it is necessary that you test the combination of settings not only by regarding the
required values that you have set, but also the so-called shut-down limits. These are actuator
settings which the ETAMATIC just takes without switching off.
Perform this test for the whole firing rate range and for all operating modes.
This test may only be dispensed with if:
– the installation is fitted with failsafe O
2
or CO monitoring which can trigger a burner shut-
down if there is incomplete combustion
or
– the installation is fitted with failsafe O
2
trim / CO control, which compensates the combus-
tion tolerances
or
– You ensure that the requested mode, has as much excess air over the whole range, that
the tolerances of the ETAMATIC are of no consequence
or
– the parameters in the ETAMATIC are set in that way, that the air defficiency tolerances
have 0 digit, i.e. there is only tolerance on the excess air side.
WARNING!
If you waive to check the shut-down limits because of one of these measures, you should
check the effectiveness of that measure instead, e.g., if there is CO/O
2
monitoring or control,
the stability of ignition should be tested at the shut-down value set
WARNING!
Due to verification in respect of authorities, test houses, quality management systems, liability
issues, etc., we strongly recommend that you document any running to shut-down limits
Check the shut-off limits at the DPS output of the ETAMATIC .
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