PCIx Specifications - Pro-Dex, Oregon Micro Systems - #29

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CONTROL SIGNAL INTERFACE INTRODUCTION PCIx User’s Manual 4-1 4. CONTROL SIGNAL INTERFACE 4.1. INTRODUCTION The PCIx family of motion controllers are available in several configurations to manage combinations of servo and step motor systems. The PCI connector incorporates all the control signals of the PCIx. The PCIx controller meets the PCI specification fully and plugs directly into a PCI slot in a computer Motherboard. 4.2. GENERAL PURPOSE I/O, LIMIT AND HOME INPUTS To facilitate system implementation, limit and home inputs are provided for each axis. Limits may be activated by mechanical switches using contact closures or other suitable active switches, such as a hall effect switch or opto-isolator that connects to ground. If the motor travels beyond its allowable limits and trips the switch, the limit switch closure removes the excitation from the affected axis. You can select the limit switch active signal state with the LH and LL command on an axis by axis basis. The behavior of the limit functionality can be controlled with the System Control Commands. The PCIx accepts TTL level limit signal inputs. The home switch provides a means to synchronize the motor controller with the load at some home, or reference, position. The home switch, when used with the software commands HM or HR, causes the motor to decelerate to a stop when the switch closes. On finding the home position, the position counters are initialized to the parameter supplied with the command. You can change the sense of the home switches to TRUE when open by use of the HH command (described on page 5-89). The Home switch and general purpose I/O signals to the PCIx are optically isolated on the board. The PCIx expects TTL level signals for the inputs. To insure these inputs operate correctly, the switch input must be connected properly to the PCIx. Refer to Figure 4-2 Opto Isolated Input Wiring Diagram for a home switch wiring example. (The same connections shown in the diagram apply to a general purpose input bit.) 4.3. CONTROL OUTPUT The PCIx is configured at the factory for control of servo motors, stepper motors or a combination of both. The servo output may be either unipolar analog (0/+10V) or bipolar analog (-10/+10 V). (See the UN and BI commands on page 5-181 and on page 5-47, respectively.) Step pulse and direction outputs are open-collector TTL level signals which will wire directly into most driver inputs. If the motor drive is not naturally pulled high (to +5VDC) you may need to add a pull-up resistor (typically 1-2.2k Ohms) from the step/clock input to +5 VDC. Refer to Figure 4-1. Auxiliary outputs are optically isolated. Each auxiliary output has a 2.2KÙ pull-up resistor on the PCIx board.