Myalarm V-LCD1 Instrukcja Obsługi Pobierz pdf (Strona 69)

NETWORKING

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System 2 Installation / Programming Manual

Trouble Shooting

If you are experiencing problems with the RS485 buss, follow the sequence of testing procedures below to

verify there is communications between all units on the System.

RS485 Line Continuity and Impedance Test

U Remove all the units from the RS485 communication line.

U Attach an ohm meter between each wire of the RS485 communications line.

U The reading should be approximately 60 ohms.

If the reading is either above or below 60 ohms, you may have wired the termination resistors incorrectly.

Refer to Figure 34.

If the reading is “infinity”, the line is open somewhere on the RS485 buss. Check all connections.

RS485 Transmission Test

U Remove all the units from the RS485 communication line.

U Attach an AC volt meter between Terminal #14 and ground (Terminal #1).

U Enter program mode. Go to Option #18 - Networking, choose Test RS485 and press #.

AC voltage should be present between 1.9VAC and 2.2VAC. This voltage will last about 10 seconds.

U Put the meter between Terminal #15 and ground (Terminal #1).

U Enter program mode. Go to Option #18 - Networking, choose Test RS485 and press #.

AC voltage should be present between 1.9VAC and 2.2VAC. This voltage will last about 10 seconds.

Now put the meter between Terminals #14 & #15.

U Enter program mode. Go to Option #18 - Networking, choose Test RS485 and press 3.

AC voltage should be between 3.8VAC and 4.4VAC. This voltage will last about 10 seconds. This test

assures the RS485 transmission ability of this circuit board.

If the proper voltages are not present, the RS485 communications circuit may be damaged and the circuit

board may have to be replaced.

RS485 Reception Test

When you have two circuit boards that have passed the transmission test, then wire these units back on the

RS485 communication line.

Go back into programming and attempt to establish communications between the master and the slave.

Visually inspect the slave unit. Look at the RS485 LEDs (lower right hand corner of circuit board). The

RS485 RXD LED (Reception) should blink every second. If this LED is not blinking, this slave is not

functioning properly.

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