Built-In Magnetic Stirrer; O Port Of The Tw Alpha Plus Titration Sample Changer; General I/O Description; Electrical Properties Of The I/O Port - SCHOTT TW alpha plus Mode D'emploi

ing cone. In this process, the sample plate is to be rotated until it latches. To remove the sample plate, just lift
it a little bit up.

4 Built-in magnetic stirrer

The TW alpha plus Titration Sample Changer is equipped with a built-in magnetic stirrer.
If the TitroLine alpha plus Titrator or a PC Software is used, for instance, this stirrer can be switched on and off
via the RS-232-C interface 1.
At the start of titration, the speed set in the method will be transferred. The stirrer will start running at that
speed. When setting the stirring speed, please do not select any setting below 10 seconds.
It the stirring speed is to be controlled by the titrator, please make sure that the setting knob is set to full stir-
ring speed, otherwise the max. possible stirring speed will be limited in accordance with the stage set on the
setting knob. The desired stirring speed can then be fine-adjusted using the rotary knob on the back panel of
the sample changer.
5 I/O port of the TW alpha plus Titration Sample Changer

5.1 General I/O description

The TW alpha plus Titration Sample Changer is equipped with a 15-channel plug connector for connecting
pump and valve modules. This I/O port can be used to connect the available devices via a cable (fig. 1, item
9). This I/O port is controlled by the computer software. A total of 4 outputs and 5 inputs is available. For the
required commands, please refer to the command list.

5.2 Electrical properties of the I/O port

The in- and outputs of the I/O port are galvanically isolated from the electronics of the titration sample changer
by optocouplers of the HCPL-0700 type. No direct circuiting of power consumers is possible. The pump and
valve modules available from SCHOTT-INSTRUMENTS can be connected directly to the I/O unit using a ca-
ble.

5.3 Inputs of the I/O port

A maximum current of 20 mA may be applied to the 4 inputs of the I/O port. An optocoupler of the HCPL-0700
type is being used. Circuiting has to be such that + 5V are applied to the common anode and the inputs can be
activated by contact to ground. The pin configuration is shown in the list below:
Input
1
2
3
4
Common anode (+ 5 V connection)
The statuses of the inputs can be inquired using the "aaIP" command.
The answer is: "aaI=10110000". The order of the zeroes and ones reflects the logic state of the inputs. The
first digit is assigned to the first input. Only the four first bit are of any relevance; for system reasons, the last 4
bits are always 0.
Pin number
1
2
3
4
13