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Description and operation mode
The IMD (insulation monitor device) SRI3/I2 continuously monitors the status of LV networks with insulated neutral (IT systems). The IMD can detect insulation
defects due to resistive component, even with the presence of DC parasitic voltages. The device is equipped with two thresholds: Alarm and Fault.
The insulation resistance measurement is performed by applying a low amplitude, 24Vp-p alternating voltage (conforms to IEC 61557-8) with a self-adaptive variable
frequency.
INSTALLATION SUGGESTIONS AND SAFETY PRECAUTION:
All installation and maintenance operations must be carried out by qualified personnel in the absence of voltage and in a total electrical safety regime, in compliance
with the safety regulations.
- Before powering the device, check that all connections have been executed correctly;
- In the case you use the IMD with the expansion SRI3/EXT2, it must be mandatory placed to the left of IMD ;
- In the presence of strong interference or discontinuity in the system, the value of the insulation resistance may be temporary replaced with the blinking message
"EVAL" as long as the measurement is unstable.
- In case of strong electromagnetic disturbances, it may happen that the symbols disappear on the display: push the last button at the bottom to restore the normal
view
IMD REGULAR ACTIVITY (GREEN DISPLAY)
- Graphic representation of the insulation resistance with an histogram dedicated to insulation resistance when it is between the 2 set thresholds (Alarm and Fault)
- Contacts status of device
The keys functions on display side are as follows:
1:TEST- push to perform the test
2: SET- push for at least 3 secs to enter/exit in/from SETUP
3: push for contrast adjustment
4: i- push for product information
SETUP (BLUE DISPLAY)
DESCRIPTION
PSW= setup password
RAL= insulation resistance alarm threshold
RF= insulation resistance Fault threshold
R3= Function of 3rd relay
FLOG= Fault relay status without alarms
RST= Reset mode
COL= background colour of display in regular activity
EXP= Expansion's presence for networks up to 1100 V
°C= Internal Temperature NTC alarm threshold or PTC
management activation**
Note: "---"Three dashes indicate that the management of relevant parameter and alarm are disabled.
** The PTC management will not be available if the expansion SRI3/EXT2 is present.
The instrument is in the normal state of measurement and supervision. The following parameters are displayed and
continuously updated:
- Insulation Resistance (Ran)
- Line voltage (when the voltage alarm thresholds are set)
- Symbol of the voltage type
- Internal temperature in °C (only if the temperature alarm threshold is set)
TEST: Push test button to start the test for checking the correct operation of device. A blinking message "TESTING" will
appear on the display. The IMD will simulates the presence of a leakage resistance, the Alarm relay will trip (and also the
third relay, if it is properly set) and the display will become yellow for few moments, subsequently the Fault relay will trip
and the display will become red. At the end of TEST, if the IMD is in automatic reset mode, it will return in the regular
activity. It must be reset by pushing the dedicated button RST if the IMD is in manual reset mode.
- push SET button for at least 3 seconds to enter in SETUP (display becomes blue)
- push NEXT button to select one after the other the parameters to modify in cyclical way
- push ▲▼ buttons to modify the selected parameter (it appears blinking)
- push SET button for at least 3 seconds to exit from SETUP and save the parameters (display returns green)
After 1 minute of inactivity, the IMD automatically exits from SETUP without saving modifications made
RANGE [DEFAULT]
000 -999 [default: 000]
5kΩ -2MΩ [default: 200kΩ]
5kΩ -2MΩ [default: 50kΩ]
A, F or A+F: it trigs if only A or only F
or A+F tripped
D: it trigs in the case of diagnostic
alarm (temperature, voltage,
transformer disconnection,
automatic test failed)
T: it trigs in the case of temperature
U: it trigs in the case of voltage alarm
DIS: it trigs in the case of transformer
disconnection alarm [default: F]
N.DE. / N.E. [default: N.DE]
MAN/AUTO [default: AUTO]
G= green B= blue W= white
L= violet N= no colour [default: G]
Yes/No [default: No] (install the
expansion on the left of IMD)
1 ÷ 90°C / PTC
[default: ---]
UMAX= Line overvoltage alarm threshold
UMIN= Line undervoltage alarm threshold
AUTOTEST= Time interval of automatic test
DELAY= FAULT tripping delay time
alarm
NODE= RS485 network node number
BAUD= Serial speed and parity bit (N= none
– E= even - 0=odd)
DESCRIPTION
20 ÷ 700V [default: 257]
20 ÷ 700V [default: 203]
0 ÷ 9999 Sec [default: 0]
RANGE [DEFAULT]
0 ÷ 72H [default: 0]
1- 247 [default: 1]
4800 ÷ 38400 bps
[default: 19200 N]
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