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HMC7000 Series Installation Guide
1010-1042 Rev 00
www.maplesystems.com
PNP-type connection (Source)
NPN-type connection (Sink)
Note: the above diagrams show that a PNP output is ‘sourcing’ current and the NPN output is ‘sinking’ current.
Which output (NPN or PNP) to use often depends upon the type of load connected. Also, PNP-type outputs are more
vulnerable to a ground short which can damage the output module. A ground short to an NPN-type output does not
damage the output module.
Digital Outputs (Relay type)
The output contacts of a relay-type digital module are typically used to control loads that require an AC power source:
If you need to connect a DC load that requires more current than the maximum available when using a PNP/NPN-type
output, this is an option. For AC loads, each relay output contact can typically handle up to 230VAC with a 2A per
contact load. For DC loads, each relay output contact can typically handle a 2A per contact load for up to 30VDC.
Analog Voltage Ratings
The 0 to 10 VDC voltage rating is applied to analog inputs and outputs. With analog inputs, the analog module writes a
data value to the assigned register (XW) based upon the measured DC voltage at the input (0 to 10 volts). Resolution
varies but is typically 16 bits (meaning a data value of 0 equates to a measurement of 0 volts, and a data value of 65535
equates to a measurement of 10 volts). Analog outputs can deliver a DC voltage of 0 to 10 volts to a load with a
minimum resistance of 1000 ohms depending upon the value in the assigned register (XY). Some analog input modules
can also be configured to measure DC voltage ranges of -10 to +10 volts, 0 to 100 millivolts, or 0 to 50millivolts.
Analog Current Ratings
The 0 to 20 mA current rating is applied to analog inputs and outputs. With analog inputs, the analog module writes a
data value to the assigned register (XW) based upon the measured DC current at the input (0 to 20 milliamps). Resolution
varies but is typically 16 bits (meaning a data value of 0 equates to no current, and a data value of 65535 equates to a
measurement of 20 mA). Analog outputs can deliver a DC current of up to 20mA to a load with a maximum resistance of
500 ohms based upon the data value in the assigned register (XY). Some analog input/output modules can also be
configured to measure 4-20mA ranges.