Table of Contents
Advertisement
If an existing control unit must be replaced with a new one, to guarantee its correct and safe operation, the sensor/
relay/supply connecting terminals must be replaced with the new terminals supplied.
ATTENTION: the monitoring unit must not be turned off during the starting phase (boot) in order to avoid
configuration data loss. In case of configuration problems, enter in PROGRAMMING and select the option "factory
default" to restore the factory settings.
WIRING NOTES
Connect the terminal on the removable terminal blocks as shown at page 10-11
AL0 alarm relay switches when the set threshold value is reached, enabling is available on all channels, see programming
step 3 on page 14.
AL1-AL2 / AUX1-AUX2 alarm relays switch when the set threshold values are reached according to the selected
intervention logic (Mode Alarm: 1-2-3-4) as shown at page 16-17.
FAULT relay switches when the monitoring unit is powered on and switches back only when the unit has registered one of
the following events:
Data memory fault (message DATA LOST / DATA ERROR) .
Sensors fault (FCC short-circuited sensor, FOC interrupted sensor) .
Insufficient supply voltage
NOTE: do not connect the FAULT relay to the transformer tripping circuit to avoid system interruptions.
The terminals 40-42 must be connected to the phases of power, while the terminal 41 must be connected to the GROUND
of the plant.
NOTE: always disconnect the unit before performing any electrical connection.
PROGRAMMED DATA DIAGNOSTICS
In case of corruption of programmed data, just after switching on, DATA ERROR appears on the display with the relevant
Fault contact. In this case, for safety reasons, the default parameters are loaded automatically (see pre-set default settings
on page 16). Eliminate DATA ERROR by pressing ENT / RST and run programming to enter the desired values.
Finally switch the unit off and back on to check the memory works correctly, if it is damaged DATA ERROR will be
displayed again (send the control unit to Tecsystem srl for repairs).
In case of failure of the internal memory, LOST DATA indication appears with the relevant Fault contact (send the control
unit to Tecsystem srl for repairs).
SENSOR CONNECTION
The PT100 sensors must be connected as shown on page 10-11, each card has 4 inputs.
All the cables transferring the sensors measurement signals must comply with the following under all circumstances:
be separated from the power cable
be made with shielded and twisted conductors
have a minimum cross section of 0.5 mm²
be firmly fixed in the terminal
cables and joints compensated for TCK probes
have tinned or silvered conductors (Pt100-Pt1000)
shielding must be connected with GROUND of the device together with the ground wire.
NOTE: to install the sensors and signal transferring cable correctly, read the sensor and SCS/SENSOR installation
rules manual.
What may happen when installation rules are not complied with.
1)The electrical field propagating from the power line of another circuit, couples capacitively with the conductors
(in particular with unscreened cables). The effect of this coupling creates a signal that overlaps the signal transmitted by
the nearby conductors, causing incorrect readings.
2) The variations in magnetic flux in the power lines may induce an electromotive force on the signal transferring cables
(in particular non-twisted cables), that, being a closed circuit, generates a current. This interference current, multiplied by
the circuit resistance, gives a voltage value that overlaps the signal to be transmitted, distorting the sensor measurement.
3) False contacts can alter the signal with the consequent variation in the temperature detected.
In specific cases, when the rules for connecting the Pt100 sensors are not complied with, the following anomalies can
occur between the SCS box and the temperature control unit:
a) incorrect temperature readings, alarms or anomalous tripping
b) mechanical / electrical fault of the sensors
c) damage to the inputs of the control unit.
12
MM453 SERIES
Advertisement
Table of Contents
