Offer > Signal separators and transmitters > 4÷20mA / 4÷20mA
T924s specifications
Output of T924s forms a passive current source (changes resistance to regulate flow of current) and uses part of resulting voltage drop to supply itself. The input part of the separator is supplied from small voltage drop in the input 4÷20mA loop. Therefore, there is no need for internal DC/DC converter that would pass energy to the input part of T924s, which means that there is no source of electromagnetic noise.
Voltage drop across the input reaches 1.7V at 20mA as demonstrated on the plot below.
Comparing that to standard solutions with approximately 50Ω input resistance causing voltage drop of ca. 1V at 20mA, the additional drop of 0.7V is small price to pay for lack of noise. T924s employs 10Ω resistor to measure the input current - remaining few mW of power is enough to supply the input circuit. Despite the minimal power consumed, starting already at ca. 1.5mA the separator linearly reproduces the input current at output. As all our separators, T924s is equipped with overvolatge and overcurrent protection. Connection example is presented below.
NOTE: T924s separators are available in two types of enclosure - with screw terminals (T924s-1, default) and spring terminals (T924s-2). Be sure to specify the desired version while ordering.
T924sP is a passive separator which introduces galvanic separation into 4÷20mA line by simply cutting the line and connecting it back through the separator. Separator consumes small amount of input signal energy which translates to additional voltage drop of 3.1V that effectively adds to voltage drop on load resistance.
Unlike most of such separators, T924sP is equipped with internal protection limiting the input (and thus the output) current to ca. 25mA.
T924sP specifications
NOTE: T924sP separators are available in two types of enclosure - with screw terminals (T924sP-1, default) and spring terminals (T924sP-2). Be sure to specify the desired version while ordering.
As other passive separators, T924s-PS allows to introduce galvanic separation into 4÷20mA line by simply cutting the line and connecting it back through the separator. T924s-PS copies the input current loop signal on output while transferring most of energy from output to input and thus supplying any loop transmitter connected there. Separator uses certain amount of energy which translates to additional voltage drop of < 4V that effectively adds to circuit voltage drop. For example, assuming 24V supply of output loop and 50Ω of output current measuring resistor, about 19V is left for input transmitter supply (at IIN = IOUT = 20mA). Internal protection circuit limits the input (and output) current to ca. 25mA.
T924s-PS specifications
T924P1 is a passive separator based on a DC transformer which introduces galvanic separation into 4÷20mA line by simply cutting the line and connecting it back through the separator. Separator consumes small amount of input signal energy which translates to additional voltage drop of 2.7V that effectively adds to voltage drop on load resistance.
Unlike most of such separators, T924P1 is equipped with internal protection limiting the input (and thus the output) current to ca. 25mA.
Though passive separators are very stable and only weakly affected by ambient temperature, they exhibit dependence on the load resistance. In case of T924P1, output load has predictable (and one of the lowest available) influence on the transfer function - deviation from nominal load of 50Ω causes change of gain leading to additional -0.03% error at 20mA for every 100Ω of load resistance increase. Load resistance is limited to 750Ω.
T924P1 specifications
In T924P2 and T924P3 every channel is independent and works similarly to described above separator T924P1, i.e. it contains a passive separator based on a DC transformer which introduces galvanic separation into 4÷20mA line by simply cutting the line and connecting it back through the separator. Small amount of input signal energy is consumed internally leading to additional voltage drop of 2.7V that effectively adds to voltage drop on load resistance.
Unlike most of such separators, every channel is equipped with internal protection limiting the input (and thus the output) current to ca. 25mA.
Though passive separators are very stable and only weakly affected by ambient temperature, they exhibit dependence on the load resistance. In case of T924P2 and T924P3, output load has predictable (and one of the lowest available) influence on the transfer function - deviation from nominal load of 50Ω causes change of gain leading to additional -0.03% error at 20mA for every 100Ω of load resistance increase. Load resistance should not exceed 750Ω.
Being a passive separator, T924PS1 (and every channel of T924PS2) allows to introduce galvanic separation into 4÷20mA line by simply cutting the line and connecting it back through the separator. In this case, however, separator copies the input current on output while transferring most of energy from output to input. This way, T924PS1 and any channel of T924PS2 may supply a loop transmitter connected to input. Certain amount of energy is lost inside the separator, which leads to additional voltage drop of 3.6V that effectively adds to circuit voltage drop. For example, assuming 24V supply of output loop and 50Ω of output current measuring resistor, over 19V is left for input transmitter supply (at IIN = IOUT = 20mA). Internal protection circuit limits the input (and output) current to ca. 25mA.
T924PS1 specifications
T924PS2 specifications
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