MTL4526 Switch operated relay 2–channel IS–output

MTL4526 Switch operated relay 2–channel IS–output

MTL4526 enables two separate IS circuits in a hazardous area to be contact controlled by one or two, on/off, control signals in a safe area. Applications include the calibration of strain–gauge bridges; changing the polarity (and thereby the tone) of an IS sounder; the testing of IS fire alarms; and the transfer of safe-area signals into an annunciator with IS input terminals not segregated from each other. The output–relay contacts are certified as non–energy–storing apparatus, and can be connected to any IS circuit without further certification, provided that separate IS circuits are such that they would remain safe if connected together.

SPECIFICATION FOR MTL4526

See also common specification

Number of channels

Two, fully floating

Location of control circuit

Safe area

Input/output characteristics

Contact/Logic mode

(Inputs suitable for switch contacts, an open–collector transistor or logic drive)

Relay energised if < 450Ω or < 1V applied

Relay de–energised if > 5kΩ or > 2V applied (35V max.)

Loop powered mode

Relay energised if >20V

Relay de-energised if <17V

Power supply failure protection

Relays de–energised if supply fails

Response time

25ms nominal

Contacts (suitable for connection to IS circuits)

1–pole changeover per channel

Contact rating

250V dc, limited to 30V dc for IS applications, 2A

(reactive loads must be suppressed)

Contact life expectancy

2 x 107operations at maximum IS load

Relay drive (see switch setting table)

Choice of "loop-powered" or "contact/logic" control, for both

channels, by switch selection. A further switch option ("1in2out")

enables either input, in contact/logic mode, to activate both outputs.