Wiring: Siemens

Wiring: Siemens

Revision: 4.10

Download this page along with the Notes and Memory Usage as a Microsoft Word file "Notes.doc" for best printing. This file is included on the disks that come with the MSP and with all driver downloads.

Sink/Source Inputs. The Inputs for the 215 and 216 and some of the expansion modules can be used as either sink or source. Each input is basically a resistor with one end of each resistor tied to individual terminals and the other ends are tied together to a terminal marked "1M" or "2M". The output on the MSP is also designed to be used as either sink or source. The MSP contains a sinking gate and pull-up resistor.

Sink/Source inputs should be wired for source for use with the MSP. If wired as source, both the input resistance and the resistance in the MSP are in parallel. Maximum current will be higher and on-state voltage will also be higher. If wired as sink the input resistance and the resistance in the MSP form a voltage divider. Maximum current will be less and the on-state voltage will be lower. For a 24 volt supply the on state voltage would be less than 14 volts which is below the 15 volt minimum on-state range specification for the input. Experience with other brands has shown that this may be acceptable in spite of printed specification. When using the standard sinking input on the S7-214 we have found it to work acceptably even though by spec is should not work. For very long distances the higher on state voltage provide additional noise immunity. For short distances the difference in noise immunity will be insignificant.

Sink Inputs. Each input is basically a resistor with one end of each resistor tied to individual terminals. The other ends are tied together to a terminal marked "1M" or "2M". This pull down resistance sinks voltage and current to common VDC.

The output on the MSP is designed to be used as either sink or source. The MSP contains a sinking gate and pull-up resistor. Sink inputs can be wired directly to the MSP.

Make sure that the PLC input module and MSP input get their 24 VDC from the same source. Following is a schematic of a typical input. "I?.?" may be any valid Input. In the single channel drivers for the S7-214 used for testing the input is I0.0 but may be changed if desired. In the multiplexed drivers for the S7-214 Channel 0 and 1 are IO.0 and IO.1 respectively but may be changed if desired.

Source Inputs. Each input is basically a resistor with one end of each resistor tied to individual terminals. The other ends are tied together to a terminal that is marked "1L" or "2L". This pull up resistance sources voltage and current from +VDC.

The output on the MSP is designed to be used as either sink or source. The MSP contains a sinking gate and pull-up resistor. Source inputs can be wired directly to the MSP.

Using the input as source would increase the level of the signal and make it more immune to noise but it would double the current required when the signal is pulled to zero volts.

Make sure that the PLC input module and MSP input get their 24 VDC from the same source. Following is a schematic of a typical input. "I?.?" may be any valid input.

Note: The true/false sense for a sourcing input is opposite that of a sinking input. In ladder logic the hardware input into the driver must be negated to provide the proper logic sense.

Relay Outputs. Relay outputs can be used as either sink or source. We recommend using them only for source since it eliminates the need of a pull up resistor. See the next note on Sourcing outputs for a schematic and more details. If using mechanical relay outputs you will have to slow the output driver down in order to debug it and not destroy the relay. We suggest using a scan time of 50 msec for the MSP analog output modules.

Output on Demand. In order to conserve the life of the relay output we suggest you add some extra logic that allows control of when the output is transmitted. If required please review the Omron or GE drives for the method.

Input/Output Scan Time Ratio. For those drivers using both inputs and relay outputs we suggest using logic that runs the output a factor of 5 times or more slower than the input. This allows the input to run at a scan time of 10 msec and the output to run a scan time of 50 msec. This is necessary only when relay outputs must be used. If required please review the Omron or GE drives for the method.

Source Outputs. All solid state DC outputs on the S7-Micro family are source. Each output is basically a transistor or gate with one end of each transistor tied to individual terminals. The other ends are tied together to a terminal that is labeled "1L+" or "2L+". This pull up contact sources voltage and current from +VDC.

The input on the MSP is sink; it is basically a resistor tied to -VDC or common. Source outputs can be wired directly to the MSP.

Make sure that the PLC output module and MSP output get their 24 VDC from the same source. Following is a schematic of a typical output. "Q?.?" may be any valid output. In the single channel drivers the output is Q0.0 but may be changed if desired. In the multiplexed drivers Channel 0 and 1 are Q0.0 and Q0.1 respectively but may be changed if desired.

Sink Outputs. Solid state DC outputs are not available on the S7-Micro family. Only relay outputs could be used as sink. Each output would basically be a contact with one end of each contact tied to individual terminals. The other ends are tied together to a terminal that is usually labeled "1L" or "2L". This pull down contact sinks voltage and current to COM VDC.

The input on the MSP is sink; it is basically a resistor tied to -VDC or common. Since both PLC output and MSP are sink a pull up resistor must be used. Sink outputs can be wired directly to the MSP with a pull-up resistor.

Make sure that the PLC output module and MSP output get their 24 VDC from the same source. Following is a schematic of a typical output. "Q?.?" may be any valid output.

Note: The true/false sense for sinking outputs is opposite that of the sourcing outputs. In ladder logic the hardware output from the driver must be negated before going to the hardware output to provide the proper logic sense.

SensorPulse Corp. • P.O. Box 8886 • Michigan City, IN 46361 • Ph: (800) 447-5900 or (219) 393-7218 • Fax: (219) 393-7318