above, according to this procedure, we know that the control of the use of the word, but also know that the stepper motor cycle with the red pulse of the number of storage locations (for Q0.0 is SMW68 and SMD72). Of course, VW100 and VD102 different data, the stepper motor speed and turning circle is not the same as the number.
that there is a need to note: M0.0-on --- PLC capture the rising edge of the pulse output after the launch, would like to stop, only to change ports of the pulse control word, and then start to PLS, the procedure is as follows:

2. High-speed counting function.
Siemens S7-200 series PLC with a high-speed counting functions; give an example to talk about the use of high-speed counting, we have adopted a common motor drive to screw rotation, we would like to turn control of the distance, how to solve this problem? Then we will be able to motor the other end with one encoder connected to the electrical circuit, the encoder also turn around the same time, according to the specifications of different pulses. Of course, these pulses of high frequency, PLC can not be used to counter rising edge of the common pulse of these can only be realized through a high-speed counting function.
start high-speed counting function, but also have control of the word

HSCO HSC1 description of the
SM37.0 SM47.0 effective reduction level control high-0 = Effective, effective 1 = low
SM37.1 SM47.1 start an effective level control at 0 = high effective, 1 = low effective
SM37.2 SM47.2 orthogonal counter rate option 0 = 4X count rate , 1 = 1X count rate
SM37.3 SM47.3 control the direction of the count by count bit = 0, 1 = count is
SM37.4 SM47.4 to count into the HSC in the direction of 0 = no update, update = 1 count direction
SM37.5 SM47.5 to the HSC into the preset value of 0 = do not update 1 Update = preset value
SM37.6 SM47.6 write to the HSC in the current value of 0 = no update, update the current value of 1 =
SM37.7 SM47.7 HSC allowed 0 = prohibit HSC, 1 = allow HSC

in the light of the above table, we have chosen to HSC1 high-speed counter, for the control of the word SMB47, now we have to start high-speed counter HSC1, by choice for the count, count to update the direction of re-setting the value of the current update: this is the case, HSC1 control of the high start-up : 11111000 into a band of 16 to F8, will start the counter when the current value stored in the SMD48, will be stored in place SMD52, specific procedures are as follows:

Similarly, if the counter in the work of the state would like to stop the counter, it must change its control of the word, the HSC start the following specific procedures:



3. PID control loop.
Siemens S7-200 series PLC's quite simple PID control, through micro / win software, a program guide, in accordance with tips, step-by-step implementation of the requirements you can attribute the PID control, PID here to talk about the three The significance of the specific parameters: P gain for the item, P greater effect on the response to the rapid adjustment in the flow valve: Set for 50% of the traffic, when traffic is currently close to 50%, more than just that if the great value of P, Then the flow valve will be shut down immediately, rather than in the control of a region. This is caused by too much of the gain. In the process of adjustment should be first to adjust the value of P would be more appropriate, then I adjust the value of its points, in the loop controller to control the current value and set value equal to the scope of bias. D for the differential, the main role is to be avoided given the value of the differential effects caused by the transition.
at the scene of the PID parameters of the adjustment process, for Siemens S7 PLC--200 my proposal is different in the control phase, a different group of PID parameters, specifically, when the current distance between the larger settings, consider using a larger P value PID parameters, if the current value Fast close to the range of settings, using a P value smaller PID parameters.