Siemens SIMATIC S5 Manual

Also see for SIMATIC S5: Manual Manual Manual Manual Manual

Description of the Firmware4–9IP244C79000–B8576–C860–02The calculated analog manipulated variables as percentages are output in message 18 forchannels 0 to 12. In the programmable controller, they can be passed on to an analog output. Percentage outputWith percentage output, the average of the manipulated variable is controlled by the pulse durationmodulation at a constant frequency (= 1/TA).The stronger or weaker control action of cooling compared with heating (e.g. water cooling) can betaken into account with 3-step controllers by setting a heating-cooling ratio (as a percentage). Ifmanual operation is intended, the manual manipulated variable to be set as a percentage iscalculated as the corresponding proportion of the sampling time according to the pulse durationmodulation.Heating switch (digital input)The heating switch (socket connector X4, pin 1) can be used to disable the controller outputs, if thiswas set for each controller individually.Pin 1, X4 connected to L+ DQs enabled;Pin 1 open DQs disabled.The disabling effect of the heating switch can be cancelled for each controller by setting bit 2 incontrol byte 2 of the controller messages.When the DQs are switched off, the controllers are stopped, the control algorithm is interrupted anderror messages cleared. This allows a ”bumpless” restart.