Functional circuit of analog signal converter
1 — input signal converter unit;
2 — microcontroller;
3 — galvanic separation unit;
4 — shaper of output current and power supply unit (current and voltage stabilizer and voltage converter);
5 — IS and reverse polarity protection unit.
Key technical characteristics
Parameter | Value |
Output circuits are intended for the work with the loads, Ohm, for the signal 0...20, 4...20 mA with the account of the communication line resistance |
not more than 450 |
Output circuits (ЭнИ-802M-Ex) are intended for the work with the loads, kiloOhm, for the signal 4...5 mA with the account of the communication line resistance |
not more than 100 |
Output circuits are intended for the work with the loads, kiloOhm, for the signal 0...5 mA with the account of the communication line resistance |
not more than 1,5 |
Insulation strength between the input supply channel and output channels, V |
1500 |
Structural design |
plastic body frame with a DIN or wall mounting option |
Weight, kg |
not more than 0,2 |
Converter ЭнИ- 802М has no built-in power supply unit. Permissible range of the supply voltage change 18…27 V for the general industrial purpose version and 22…24 V for the explosion-proof one. Consumed power is not more than 0,6 W.
IS circuits
Measuring converters can be manufactured in the IS version by the order.
Input IS circuits in compliance with the requirements set in GOST R 30852.0-2002, GOST R 30852.10-2002 have the intrinsic safety level "ia – extra-explosion-proof" or "ib - explosion-proof" with the parameters for the explosion-proof electric equipment of the subgroups IIC. The limit parameters of external IS electric circuits shall not exceed the values given in the Table below.
Со, mkF | Lo, mH | Uо, W | Iо, mA | Pо, W |
0,1 |
1,5 |
25,2 |
100 |
0,6 |
где:
Со — maximum capacity of an IS circuit;
Lо — maximum induction of an IS circuit;
Uo — maximum output voltage;
Io — maximum output current;
Ро — maximum output voltage.
A separating element between IS and spark-hazardous circuits is the IS barrier on duplicated stabilitrons, consecutively connected resistors and protectors having a galvanic connection with a grounding circuit and contained into a single integral structure in compliance with GOST R 30852.10-2002.
Communication line cable resistance shall not exceed 25 Om.
In compliance with the requirements stipulated in GOST R 30852.0-2002, GOST R 30852.10-2002 power supply units are installed outside explosion-hazardous areas.