CROPICO LTD – DO7
Issue 7/2001
10
It should also be noted that some spade tags and crocodile clips can produce high thermal emfs
when warmed, particularly nickel-plated brass types. This can cause problems when, for example,
connecting too hot motor windings. The solution is to use plain copper or brass connections
keeping them clean and oxide-free.
12. REMOTE
If a footswitch or other similar external switch is plugged into the REMOTE socket, it will behave as
an ON key. This feature is particularly useful when used with the PRINT LAST function to enable
"hands free" operation during measurement, with the results printed on an external printer. For
switch connections see page 15.
13. PRINTER OUTPUT
The print format will be as follows:
SIGN VALUE UNIT (measuring mode)
example: + 600.0 m ohm (+ve)
- 600.0 m ohm (-ve)
600.0 m ohm (Ave)
The value printed will be followed by a line feed carriage return.
Should the instrument display read over-range then the value will be printed as
- - - -
For cable connection details see page 16.
Print All
All measured values will be sent to the printer port (RS232) when "ON". This key toggles ON/OFF.
Print Last
The last measured value only will be sent to the printer port (RS232). This is defined as the last
value measured when switching from "ON" to "STBY". This key toggles ON/OFF.
Baud Rate
This key will display the currently set value when pressed. To change the value, press CLE to
clear and then use the keyboard to enter the new value, finishing with OK. If the new entered value
is a valid rate, then it will be stored and retained in the NVRAM. If it is invalid a long bleep will
sound and it will reset to the last value. The valid Baud Rates are: 75, 110, 150, 300, 600, 1200,
2400, 4800, 9600, 19200. The format is fixed at 8-bit data, 1 start bit, 1 stop bit and no parity.
14. PROTECTION
Every effort has been made to protect the instrument against voltages being applied to the
terminals. A large 6 Amp fuse is fitted internally to the C measuring line and a gas discharge tube,
GDT, is across the C terminals. If voltages above approximately 90V are applied to the measuring
terminals, the GDT will strike, effectively shorting the C terminals through the 6 Amp protective
fuse, which will interrupt the circuit.
The fuse fitted will interrupt up to 40,000 Amps. The P terminals are not fused and will withstand
up to 460 Volts without damage to the instrument.
WARNING !
To replace the protection fuse, the top instrument panel should be removed, but only after the
mains supply and all input connections are removed. The protection fuse is located on the main
printed circuit board. Only replace with the correct fuse rating.
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