Watson-Marlow 704U - Manual (Page 4)

Watson-Marlow Bredel E-Manuals
http://www.watson-marlow.it/pdfs-global/m-704su-gb-03.htm[10/07/2012 14:21:14]
8 Troubleshooting
Should the pump fail to operate, make the following checks to determine whether or not
servicing is required.
Check that the power switch is on.
Check the mains supply is available at the pump.
Check the voltage selector switch is in the correct position.
Check the fuse in the mains socket.
Check that the pump is not stalled by incorrect fitting of tubing.
9 704S and 704U Manual operation
Switch on mains power by turning the rotary switch on top of the drive to "I".
Change the set speed by pressing the
or key. The 704S and 704U speed control
ratio is better than 50:1. This will give a minimum rotor speed of 7rpm on the 360rpm
drive.
Change direction by pressing the CW/CCW key.
Select the maximum speed: press the
key and the Max key together.
Select the minimum speed: press the key and the Max key together.
The keypad has a locking facility to avoid resetting or tampering. If the pump is
stopped, press Stop until the padlock symbol illuminates. If the pump is running, press
Start until the padlock symbol illuminates. All keys will be disabled except for Start and
Stop. Press either of these keys until the padlock symbol extinguishes to unlock the
keypad.
The pump can be set to automatically restart in its operating state set prior to power
interruption, or set so that after power is reconnected the pump will remain stopped. To
invoke the auto-restart facility switch off power to the pump at the mains supply. Press
the Start key while the mains supply is switched back on until the ! symbol illuminates.
Now press Start to start the pump. This facility can be cancelled by turning the mains
supply off and then pressing the Stop key while turning the mains supply back on. The
! symbol will not be illuminated.
Press Start to start the pump. Press Stop to stop the pump.
10 704U Automatic operation
Ensure the Man/Aut keypad switch on the front panel is switched to the auto position so
that the Aut symbol illuminates.
The pump will accept external control signals through the 25 pin cage clamp connector on
the back panel. The auto control cable glands mounting thread size is PG7, accepting 3.0-
5.0mm cable. Remove the cover plate ensuring that the gasket is not damaged.
The pump is controllable by an analogue process signal of up to 30V or 32mA. The pump
will provide an increasing flow rate for rising control signal (non-inverted response) or an
increasing flow rate for falling control signal (inverted response).
Signal offset is the process signal level which has to be reached in order for the pump
rotor to start rotating.
Signal range is the change in process signal level necessary to produce the required
change in pump rotor speed.
For example, when using a 4mA to 20mA process signal:
Pump response Signal offset Signal range
Non-inverted 4mA 16mA
Inverted 20mA 16mA
For voltage modes a stable, variable DC voltage source can