Watson-Marlow 505Du User Manual

Page 12

Auto-control

Never apply mains voltage across any pins on the 25D socket as
permanent damage, not covered by warranty, will result. Up to 30V may
be applied across pins 4 and 17, and 5V TTL on pins 7 and 5, but no
voltage should be applied across other pins as permanent damage, not
covered by warranty, may result.

Several methods or control can be used with the 505Du. For simple applications
the pump can be stopped/started and reversed by using a make/break switch or
by TTL compatible logic. These can be used either in the manual or auto mode.
Remote speed control can be obtained by using an analogue signal or a
potentiometer with the pump in the auto mode set for a 0-12V signal.

The 505Du is shipped from Watson-Marlow with the auto-control circuit set for a
0-10V input signal. Under analogue control the pump displays rpm to the nearest
rpm. The actual motor control accuracy of the 55rpm drive is 0.1rpm, whilst the
accuracy of the 220rpm drive is 0.25rpm. For more accurate speed
measurement apply a digital tachometer to the drive shaft of the pump whilst
operating under ambient conditions.

To use the pump under analogue control, identify the 25 pin "D" connector on the
rear of the pump. All wiring diagrams refer to the pin-outs shown below:

Connections for current control

Circuit impedance 250 ohms. Maximum current signal
32mA. Fit a link between pins 3 and 16 and connect the
signal wires to pin 4(+) and pin 17(-) of the 25D plug.

Connections for voltage control

Circuit impedance 100K ohms. Maximum voltage signal
30V. Polarity shown for non-inverted response. Reverse
polarity for inverted response.

Assume 4-20mA analogue control is required For a speed control of 0-
220rpm and that you accept the factory calibration of the signal conditioner on
the control circuit. Start from the main menu:

M A N U A L

A U T O

Step, Step to second screen

C A L I B

S E T U P

Step to SETUP and press Enter

Analogue

Signal in

Current

Voltage

Signal in

Signal setup