Multi pump setup

Multiple pumps can be controlled from a single serial port using a combination of RS‑232 and RS-485 serial communication.  The first pump is called the host and it is connected to the computer via RS-232.  The MicroLynx is configured to communicate over RS-232 with the following communications settings: 9600 baud, No parity checking, 8 data bits, 1 stop bit, and no flow control.

 The MicroLynx is equipped with two communications ports on the communications connector and when this controller is set up as a host, it echoes all serial communication to its second RS-485 port.  Additional controllers can be daisy chained on the RS-485 loop.  Of course, each controller must be configured with a different address.  The easiest way to do this when you want to link seven or less pumps is to set the dip switches on the controllers for the desired address.  The following table shows the dip switch settings for devices A through G.  To connect more than 7 controllers, you must use the DN command which is described in more detail in the MicroLynx manual.

When you set any of the dip switches, the PARTY mode variable for that controller will automatically be set to TRUE to indicate that all further communications must occur in Party mode.

There are two distinctive components to Party mode communication.

1. All commands are preceded by the device address, e.g. AMOVR 100 to dispense 100 µL from the pump controller with the address A (address must be CAPS).
2. All commands must be terminated with a line feed (LF).  You send a line feed when you type Ctrl-J.  Many communication packages can be set up to send a LF whenever you hit the Enter (carriage return) key.

Note: when ever you start typing all controllers except the one whose address has been typed stop interpreting the typed characters until the line feed is entered.  So if you type an invalid command or address you must type Ctrl-J to “get the attention” of all the controllers.

The cable that connects the multiple controllers will have the following pin-outs.  Controllers 2 through n are all connected in the same way to Controller 1.

This table also sets out the values of certain important settings on each controller.

Procedure

1. Begin by sequentially placing each controller at the connector closest to the 9 pin D-shell connector.  This is the only connector hooked up to the RS-232 port.  You can use this connector to set all the relevant parameters and test communication with each individual controller.
2. Ensure that the address setting on the dip switches has been set before you hook up the controller
3. Send all command settings preceded by the address (addresses are case sensitive) and terminated with Ctrl-J (LF).  The command settings are given in the table above.  Remember to make all changes to settings permanent by using the SAVE command (again proceeded by the address and terminated with Ctrl-J (LF)).
4. Once all controllers have been configured, connect them to the cable and test the communication.  A useful command to use is the PRINT Command.  aPRINT SER will give you the serial number for the addressed controller (a=the relevant address).