Monroe Electronics Electrostatic Fieldmeter - Static Monitor - model 177A - Manual (Page 29)

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Selecting this window from the MONITOR drop-down menu on the main
screen permits reading and writing to the front panel displays, LEDs, and
exercising the system relay contacts. Before using this feature, the 177A
must be connected and set to Group-Disable to permit control of these
items. This feature is helpful in testing all external relay contact wiring to
external devices.
To turn an LED or relay contact on or off or to obtain it’s status, click on the
appropriate box on the Set LED/Relay grid, then click the On, Off, or Read
button. Remember that the relay contacts are set to be “fail safe” meaning
that when conditions are O.K. in normal operation, these contacts are
closed. They will then open under caution or alarm conditions or system
failures. See Figure 8, on page 10, for examples of connecting external
devices.
To read a register (channel display), select the channel in the Channel
Display box in the right of the Diagnostic window, and then click the Read
button. The selected channel display data is shown in the window below the
channel display pull-down.
Numerical or text data can be written to any channel display by first selecting
the channel in the Channel Display pull-down in the right of the Diagnostic
window, entering the data to be written in the boxes below and then clicking
the Write Number or Write Text button.
Display decimal points can be checked by using the Set Decimal box.
Select the decimal position to be written and then click the Set Decimal
button. The display should show the correct decimal point with associated
zeros. This only checks the functionality of the decimal point and does not
alter the setting used in the Edit Channel screen of the Program Setup.
Any settings written to the unit during diagnostic checks are automatically
canceled when the unit is cycled back to Group Enable.
The Read / Write commands use MODBUS protocol. The addresses for the
relays, LEDs, and displays are listed below and in the Coil Address Table in
the
help menu of the Read / Write Coils window.
Register (Channel) addresses for MODBUS communications:
Channel 1 Display =Register 0
Channel 2 Display =Register 1
Channel 3 Display =Register 2
Channel 4 Display =Register 3
Coil (LED and Relays) addresses:
Channel 1 Alarm LED (red) = Coil 0 ---- Alarm Relay = Coil 12
Channel 2 Alarm LED (red) = Coil 1 ---- Alarm Relay = Coil 13
Channel 3 Alarm LED (red) = Coil 2 ---- Alarm Relay = Coil 14
Channel 4 Alarm LED (red) = Coil 3 ---- Alarm Relay = Coil 15
Channel 1 Warning (amber LED) = Coil 0 ---- Warning Relay = Coil 16
Channel 2 Warning (amber LED) = Coil 1 ---- Warning Relay = Coil 17
Channel 3 Warning (amber LED) = Coil 2 ---- Warning Relay = Coil 18
Channel 4 Warning (amber LED) = Coil 3 ---- Warning Relay = Coil 19
Channel 1 OK LED (green) = Coil 8 ---- OK Relay = Coil 20
Channel 2 OK LED (green) = Coil 9 ---- OK Relay = Coil 21
Channel 3 OK LED (green) = Coil 10 ---- OK Relay = Coil 22
Channel 4 OK LED (green) = Coil 11 ---- OK Relay = Coil 23
System Alarm Relay = Coil 24
To exit the Diagnostic window, click on the Close button.
To close the program software click on Exit on the main program window.