3.2 Proportional flow rate control (controller only)

The gas flow rate can be regulated over the whole range of 0.0 to 5.0 l/min for the MASSFLOW 5000 (or 0 to 500 ml/min for the MASSFLOW 500) by an external DC voltage 0 to 10 V applied to the contact no. 1 of the rear side socket (REMOTE). The 0V line must be connected to the contact no. 3 of the same socket (Figure 6.2-1). The remote control is activated by pressing the REMOTE button. The corresponding REMOTE LED is lit.

For safety reasons the voltage of the external signal must not exceed 48 V to earth!

3.3 PC control

If the instrument has been equipped with the optional RS-232 or RS-485 interface, it can be controlled digitally, e.g. from a PC by PNet control software.

The line should be connected according to Figure 6.2-1. (A resistor of 100 ohms should be connected between both RS-485 lines, if it is not already present. This resistor is not part of MASSFLOW or any other LAMBDA instrument.) When the digital control is activated the REMOTE LED is on and all manual commands (with exception of the SET button) are blocked.

For the MASSFLOW meter (flow measurement only) the measured flow values can be accessed over the RS-protocol as well as the total gas volume, if the internal INTEGRATOR (optional) has been installed.

3.4 Setting up the address for PC control

The digital control requires an attribution of an appropriate address to the MASSFLOW. This is done in the following way: Pull out the power supply cable from the rear of the MASSFLOW.